feat(android): app nativa Kotlin/Compose (login, rooms, chat)

App Android Material 3, tema oscuro con acento índigo/violeta que replica el
look & feel de la app web (web/src):

- Login: identidad + contraseña, candado de marca, estilo Card.
- Lista de rooms: avatar+handle, buscador rooms/usuarios/mensajes, items con
  candado (E2E) / hash (cleartext), hora, último mensaje y badge de no leídos.
- Chat estilo Element: avatar+nombre+hora+texto, composer redondeado con send.

Arquitectura por capas: UnibusRepository aísla la UI de la fuente de datos.
MockUnibusRepository (en memoria) alimenta la iteración de diseño;
BindingUnibusRepository implementa la misma interfaz sobre el binding gomobile
(unibus.aar) para conectar el bus real sin tocar las pantallas. AppViewModel
orquesta el estado; navegación por estado (login -> rooms -> chat), KISS.

Build: ./gradlew assembleDebug (AGP 8.5.2, Gradle 8.7, Kotlin 1.9.24,
Compose BOM 2024.06.00, compileSdk 34, minSdk 21). El .aar se regenera con
mobile/gen_aar.sh (no se versiona, 38MB).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -14,3 +14,7 @@ worker.id
 /chat
 *.exe
 registry.db
+
+# local workspace (no committear: replace absoluto al registry)
+go.work
+go.work.sum

android/.gitignore

@@ -0,0 +1,15 @@
+# Android / Gradle build artifacts
+*.iml
+.gradle/
+/local.properties
+/.idea
+.DS_Store
+/build
+/app/build
+/captures
+.externalNativeBuild
+.cxx
+
+# binding gomobile regenerable (38MB): ver mobile/gen_aar.sh
+/app/libs/*.aar
+/app/libs/*-sources.jar

android/app/build.gradle.kts

@@ -0,0 +1,75 @@
+plugins {
+    id("com.android.application")
+    id("org.jetbrains.kotlin.android")
+    id("org.jetbrains.kotlin.plugin.serialization")
+}
+
+android {
+    namespace = "com.unibus.app"
+    compileSdk = 34
+
+    defaultConfig {
+        applicationId = "com.unibus.app"
+        minSdk = 21
+        targetSdk = 34
+        versionCode = 1
+        versionName = "0.1.0"
+        // The unibus.aar ships native libgojni.so for these ABIs. Limit the APK
+        // to the desktop/emulator + phone ABIs we actually target.
+        ndk {
+            abiFilters += listOf("arm64-v8a", "armeabi-v7a", "x86", "x86_64")
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro",
+            )
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    kotlinOptions {
+        jvmTarget = "17"
+    }
+    buildFeatures {
+        compose = true
+    }
+    composeOptions {
+        // Compose compiler matching Kotlin 1.9.24.
+        kotlinCompilerExtensionVersion = "1.5.14"
+    }
+    packaging {
+        resources {
+            excludes += "/META-INF/{AL2.0,LGPL2.1}"
+        }
+    }
+}
+
+dependencies {
+    // gomobile binding over pkg/client (real end-to-end crypto on device).
+    implementation(files("libs/unibus.aar"))
+
+    implementation("androidx.core:core-ktx:1.13.1")
+    implementation("androidx.activity:activity-compose:1.9.0")
+    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.8.2")
+    implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.8.2")
+
+    val composeBom = platform("androidx.compose:compose-bom:2024.06.00")
+    implementation(composeBom)
+    implementation("androidx.compose.ui:ui")
+    implementation("androidx.compose.ui:ui-graphics")
+    implementation("androidx.compose.material3:material3")
+    implementation("androidx.compose.material:material-icons-extended")
+    implementation("androidx.compose.ui:ui-tooling-preview")
+    debugImplementation("androidx.compose.ui:ui-tooling")
+
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.3")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.8.1")
+}

android/app/libs/README.md

@@ -0,0 +1,12 @@
+# libs/
+
+`unibus.aar` (binding gomobile sobre `pkg/client`, ~38 MB con `libgojni.so` para
+4 ABIs) vive aquí pero **no se versiona** — es un artefacto de build reproducible.
+
+Regenéralo con:
+
+```bash
+../../mobile/gen_aar.sh
+```
+
+(desde la raíz del repo: `./mobile/gen_aar.sh`). Requiere Go + gomobile + Android NDK.

android/app/proguard-rules.pro

@@ -0,0 +1,4 @@
+# gomobile binding: keep the generated Go<->Java bridge classes intact so the
+# JNI layer can find them by name at runtime.
+-keep class go.** { *; }
+-keep class com.unibus.core.mobile.** { *; }

android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- The bus is reached over the network (NATS data plane + control plane). -->
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+
+    <application
+        android:allowBackup="true"
+        android:label="unibus"
+        android:icon="@mipmap/ic_launcher"
+        android:theme="@style/Theme.Unibus"
+        android:supportsRtl="true">
+
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:theme="@style/Theme.Unibus">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

android/app/src/main/java/com/unibus/app/AppViewModel.kt

@@ -0,0 +1,88 @@
+package com.unibus.app
+
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.unibus.app.data.Message
+import com.unibus.app.data.MockUnibusRepository
+import com.unibus.app.data.Room
+import com.unibus.app.data.UnibusRepository
+import com.unibus.app.data.User
+import kotlinx.coroutines.launch
+
+/**
+ * Estado de la app. Orquesta el [UnibusRepository] (mock por defecto) y expone
+ * estado observable a Compose. Cambiar el repo por [com.unibus.app.data.BindingUnibusRepository]
+ * conecta la UI al bus real sin tocar las pantallas.
+ */
+class AppViewModel(
+    private val repo: UnibusRepository,
+) : ViewModel() {
+
+    // Constructor no-arg para que androidx `viewModel()` lo instancie por
+    // reflexión. Por defecto usa el repositorio mock (iteración de diseño).
+    constructor() : this(MockUnibusRepository())
+
+    var user by mutableStateOf<User?>(null)
+        private set
+    var rooms by mutableStateOf<List<Room>>(emptyList())
+        private set
+    var activeRoomId by mutableStateOf<String?>(null)
+        private set
+    var messages by mutableStateOf<List<Message>>(emptyList())
+        private set
+    var connecting by mutableStateOf(false)
+        private set
+    var error by mutableStateOf<String?>(null)
+        private set
+
+    val activeRoom: Room?
+        get() = rooms.firstOrNull { it.id == activeRoomId }
+
+    fun connect(handle: String, password: String) {
+        if (connecting) return
+        connecting = true
+        error = null
+        viewModelScope.launch {
+            repo.connect(handle, password)
+                .onSuccess {
+                    user = it
+                    rooms = repo.listRooms()
+                }
+                .onFailure { error = it.message ?: "No se pudo conectar" }
+            connecting = false
+        }
+    }
+
+    fun openRoom(id: String) {
+        activeRoomId = id
+        messages = repo.messagesOf(id)
+        repo.subscribe(id) { incoming ->
+            if (activeRoomId == id) messages = messages + incoming
+        }
+    }
+
+    fun closeRoom() {
+        activeRoomId = null
+        messages = emptyList()
+    }
+
+    fun send(text: String) {
+        val rid = activeRoomId ?: return
+        val body = text.trim()
+        if (body.isEmpty()) return
+        viewModelScope.launch {
+            repo.send(rid, body).onSuccess { messages = messages + it }
+        }
+    }
+
+    fun logout() {
+        repo.close()
+        user = null
+        rooms = emptyList()
+        activeRoomId = null
+        messages = emptyList()
+    }
+}

android/app/src/main/java/com/unibus/app/MainActivity.kt

@@ -0,0 +1,63 @@
+package com.unibus.app
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.setContent
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.lifecycle.viewmodel.compose.viewModel
+import com.unibus.app.ui.ChatScreen
+import com.unibus.app.ui.LoginScreen
+import com.unibus.app.ui.RoomListScreen
+import com.unibus.app.ui.theme.LocalUnibusColors
+import com.unibus.app.ui.theme.UnibusColors
+import com.unibus.app.ui.theme.UnibusTheme
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            UnibusTheme {
+                CompositionLocalProvider(LocalUnibusColors provides UnibusColors()) {
+                    UnibusApp()
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Navegación por estado (sin librería de routing — KISS): el usuario fluye
+ * Login → lista de rooms → chat, igual que la web pero en una sola columna.
+ */
+@Composable
+private fun UnibusApp(vm: AppViewModel = viewModel()) {
+    val user = vm.user
+    val activeRoom = vm.activeRoom
+
+    when {
+        user == null -> LoginScreen(
+            connecting = vm.connecting,
+            error = vm.error,
+            onLogin = { handle, password -> vm.connect(handle, password) },
+        )
+
+        activeRoom == null -> RoomListScreen(
+            user = user,
+            rooms = vm.rooms,
+            onSelect = { vm.openRoom(it) },
+            onLogout = { vm.logout() },
+        )
+
+        else -> {
+            BackHandler { vm.closeRoom() }
+            ChatScreen(
+                room = activeRoom,
+                messages = vm.messages,
+                onSend = { vm.send(it) },
+                onBack = { vm.closeRoom() },
+            )
+        }
+    }
+}

android/app/src/main/java/com/unibus/app/data/BindingRepository.kt

@@ -0,0 +1,157 @@
+package com.unibus.app.data
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import com.unibus.core.mobile.FrameListener
+import com.unibus.core.mobile.Mobile
+import com.unibus.core.mobile.Session
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import java.io.File
+
+/**
+ * Implementación real sobre el binding gomobile (pkg/client): cifrado de extremo
+ * a extremo EN el dispositivo, igual que cualquier otro peer del bus. Comparte
+ * interfaz con [MockUnibusRepository], así que la UI no cambia al enchufarla.
+ *
+ * Estado: cableado completo y compilable contra unibus.aar. La iteración 1 de la
+ * app corre sobre el mock para iterar el diseño; para activar el bus real basta
+ * con instanciar este repo en [com.unibus.app.MainActivity] pasando las URLs del
+ * bus y (si el bus exige TLS+auth) el ca.crt en assets.
+ *
+ * Contrato de membresía (issue 0006e): tras CreateRoom / Join / Invite hay que
+ * llamar [refresh] ANTES de subscribe/publish en esa room, o un bus seguro
+ * deniega el subject. refresh() además tira las suscripciones: re-suscribir luego.
+ */
+class BindingUnibusRepository(
+    context: Context,
+    private val natsURL: String,
+    private val ctrlURL: String,
+) : UnibusRepository {
+
+    private val appContext = context.applicationContext
+    private val mainHandler = Handler(Looper.getMainLooper())
+    private val json = Json { ignoreUnknownKeys = true }
+
+    private var session: Session? = null
+    private var user: User? = null
+
+    @Serializable
+    private data class RoomDTO(
+        val room_id: String,
+        val subject: String,
+        val epoch: Int = 0,
+        val encrypted: Boolean = false,
+        val role: String = "",
+    )
+
+    /** Ruta sandbox de la identidad de larga duración (claves privadas). */
+    private fun identityPath(): String =
+        File(appContext.filesDir, "identity.key").absolutePath
+
+    /**
+     * Copia ca.crt de assets a un fichero local y devuelve su ruta; "" si no hay
+     * (bus de desarrollo en texto plano). El binding pinea TLS a este CA cuando
+     * la ruta no está vacía.
+     */
+    private fun caPathOrEmpty(): String {
+        return try {
+            val out = File(appContext.filesDir, "ca.crt")
+            appContext.assets.open("ca.crt").use { input ->
+                out.outputStream().use { input.copyTo(it) }
+            }
+            out.absolutePath
+        } catch (_: Exception) {
+            ""
+        }
+    }
+
+    override suspend fun connect(handle: String, password: String): Result<User> =
+        withContext(Dispatchers.IO) {
+            try {
+                // La identidad se persiste cifrada en el sandbox; password la
+                // desbloquea en una iteración futura (hoy LoadOrCreateIdentity la
+                // crea/lee directamente). handle es la etiqueta visible local.
+                Mobile.generateIdentity(identityPath())
+                val s = Mobile.newSession(identityPath(), natsURL, ctrlURL, caPathOrEmpty())
+                session = s
+                val u = User(id = s.endpointID(), handle = handle)
+                user = u
+                Result.success(u)
+            } catch (e: Exception) {
+                Result.failure(e)
+            }
+        }
+
+    override suspend fun listRooms(): List<Room> = withContext(Dispatchers.IO) {
+        val s = session ?: return@withContext emptyList()
+        val raw = runCatching { s.listRoomsJSON() }.getOrDefault("[]")
+        val dtos = runCatching { json.decodeFromString<List<RoomDTO>>(raw) }.getOrDefault(emptyList())
+        dtos.map {
+            Room(
+                id = it.room_id,
+                name = it.subject,
+                encrypted = it.encrypted,
+                lastMessage = "",
+                lastTs = System.currentTimeMillis(),
+                unread = 0,
+                messages = emptyList(),
+            )
+        }
+    }
+
+    override fun messagesOf(roomId: String): List<Message> = emptyList()
+
+    override fun subscribe(roomId: String, onMessage: (Message) -> Unit) {
+        val s = session ?: return
+        val myId = user?.id
+        // FrameListener.onFrame llega en una goroutine de NATS: saltamos al hilo
+        // principal antes de tocar estado de Compose.
+        val listener = object : FrameListener {
+            override fun onFrame(rid: String, sender: String, msgID: String, text: String) {
+                val msg = Message(
+                    id = msgID,
+                    sender = sender,
+                    body = text,
+                    ts = System.currentTimeMillis(),
+                    mine = sender == myId,
+                )
+                mainHandler.post { onMessage(msg) }
+            }
+        }
+        runCatching { s.subscribe(roomId, listener) }
+    }
+
+    override suspend fun send(roomId: String, text: String): Result<Message> =
+        withContext(Dispatchers.IO) {
+            val s = session ?: return@withContext Result.failure(IllegalStateException("sin sesión"))
+            try {
+                s.publish(roomId, text)
+                Result.success(
+                    Message(
+                        id = "local-${System.currentTimeMillis()}",
+                        sender = user?.id ?: "yo",
+                        body = text,
+                        ts = System.currentTimeMillis(),
+                        mine = true,
+                    ),
+                )
+            } catch (e: Exception) {
+                Result.failure(e)
+            }
+        }
+
+    /** Reaplica permisos tras un cambio de membresía. Re-suscribir después. */
+    suspend fun refresh(): Result<Unit> = withContext(Dispatchers.IO) {
+        runCatching { session?.refreshSession(); Unit }
+    }
+
+    override fun close() {
+        runCatching { session?.close() }
+        session = null
+        user = null
+    }
+}

android/app/src/main/java/com/unibus/app/data/MockData.kt

@@ -0,0 +1,59 @@
+package com.unibus.app.data
+
+// Datos de muestra para iterar el diseño sin el bus conectado (espejo de mock.ts).
+private const val NOW = 1749300000000L
+private fun m(n: Int): Long = NOW - n * 60_000L
+
+val MOCK_ROOMS: List<Room> = listOf(
+    Room(
+        id = "general",
+        name = "general",
+        encrypted = true,
+        lastMessage = "¿Lo desplegamos hoy?",
+        lastTs = m(2),
+        unread = 3,
+        messages = listOf(
+            Message("1", "ana", "Buenas, ¿cómo va el cluster?", m(40)),
+            Message("2", "lucas", "Los 3 nodos en R3, quorum verde", m(38), mine = true),
+            Message("3", "ana", "Brutal. ¿Y el frontend?", m(30)),
+            Message("4", "leo", "Primera iteración lista, estilo Element", m(6)),
+            Message("5", "ana", "¿Lo desplegamos hoy?", m(2)),
+        ),
+    ),
+    Room(
+        id = "board",
+        name = "board · privado",
+        encrypted = true,
+        lastMessage = "Os paso el acta cifrada",
+        lastTs = m(95),
+        unread = 0,
+        messages = listOf(
+            Message("1", "ceo", "Reunión a las 18:00", m(120)),
+            Message("2", "lucas", "Anotado", m(96), mine = true),
+            Message("3", "ceo", "Os paso el acta cifrada", m(95)),
+        ),
+    ),
+    Room(
+        id = "bots",
+        name = "bots",
+        encrypted = false,
+        lastMessage = "echo: ping",
+        lastTs = m(210),
+        unread = 0,
+        messages = listOf(
+            Message("1", "lucas", "!ping", m(212), mine = true),
+            Message("2", "echobot", "echo: ping", m(210)),
+        ),
+    ),
+    Room(
+        id = "infra",
+        name = "infra",
+        encrypted = true,
+        lastMessage = "magnus + homer + datardos OK",
+        lastTs = m(330),
+        unread = 1,
+        messages = listOf(
+            Message("1", "leo", "magnus + homer + datardos OK", m(330)),
+        ),
+    ),
+)

android/app/src/main/java/com/unibus/app/data/Models.kt

@@ -0,0 +1,30 @@
+package com.unibus.app.data
+
+/**
+ * Modelos de dominio de la UI. En la iteración 1 se llenan con datos mock; más
+ * adelante vendrán del binding gomobile (pkg/client) a través de
+ * [UnibusRepository]. Reflejan los tipos de la app web (types.ts).
+ */
+
+data class User(
+    val id: String,
+    val handle: String,
+)
+
+data class Message(
+    val id: String,
+    val sender: String, // handle
+    val body: String,
+    val ts: Long, // epoch ms
+    val mine: Boolean = false,
+)
+
+data class Room(
+    val id: String,
+    val name: String,
+    val encrypted: Boolean,
+    val lastMessage: String,
+    val lastTs: Long,
+    val unread: Int,
+    val messages: List<Message>,
+)

android/app/src/main/java/com/unibus/app/data/Repository.kt

@@ -0,0 +1,74 @@
+package com.unibus.app.data
+
+/**
+ * Capa de repositorio que aísla la UI de la fuente de datos. La iteración 1 usa
+ * [MockUnibusRepository] (en memoria) para iterar el diseño. Cuando se enchufe
+ * el bus real, [BindingUnibusRepository] (en BindingRepository.kt) implementa
+ * esta misma interfaz sobre el binding gomobile (pkg/client), sin tocar la UI.
+ */
+interface UnibusRepository {
+    /** Desbloquea/crea la identidad y conecta al bus. Devuelve el usuario logueado. */
+    suspend fun connect(handle: String, password: String): Result<User>
+
+    /** Rooms a las que pertenece el peer. */
+    suspend fun listRooms(): List<Room>
+
+    /** Mensajes históricos conocidos de una room (mock: los del propio Room). */
+    fun messagesOf(roomId: String): List<Message>
+
+    /**
+     * Suscribe a una room. [onMessage] se invoca por cada mensaje entrante.
+     * Las implementaciones que vienen del bus DEBEN entregar [onMessage] en el
+     * hilo principal (el binding lo recibe en una goroutine de NATS).
+     */
+    fun subscribe(roomId: String, onMessage: (Message) -> Unit)
+
+    /** Publica texto en la room. */
+    suspend fun send(roomId: String, text: String): Result<Message>
+
+    /** Cierra la sesión. */
+    fun close()
+}
+
+/**
+ * Implementación en memoria: arranca con [MOCK_ROOMS] y acumula los mensajes que
+ * el usuario envía. No toca red ni binding — sirve para construir y revisar la UI.
+ */
+class MockUnibusRepository : UnibusRepository {
+    private var user: User? = null
+    private val sent = mutableMapOf<String, MutableList<Message>>()
+
+    override suspend fun connect(handle: String, password: String): Result<User> {
+        val u = User(id = handle, handle = handle)
+        user = u
+        return Result.success(u)
+    }
+
+    override suspend fun listRooms(): List<Room> = MOCK_ROOMS
+
+    override fun messagesOf(roomId: String): List<Message> {
+        val base = MOCK_ROOMS.firstOrNull { it.id == roomId }?.messages.orEmpty()
+        return base + (sent[roomId].orEmpty())
+    }
+
+    override fun subscribe(roomId: String, onMessage: (Message) -> Unit) {
+        // El mock no recibe tráfico entrante; el eco lo gestiona la UI al enviar.
+    }
+
+    override suspend fun send(roomId: String, text: String): Result<Message> {
+        val handle = user?.handle ?: "yo"
+        val msg = Message(
+            id = "local-${System.currentTimeMillis()}",
+            sender = handle,
+            body = text,
+            ts = System.currentTimeMillis(),
+            mine = true,
+        )
+        sent.getOrPut(roomId) { mutableListOf() }.add(msg)
+        return Result.success(msg)
+    }
+
+    override fun close() {
+        user = null
+    }
+}

android/app/src/main/java/com/unibus/app/ui/ChatScreen.kt

@@ -0,0 +1,203 @@
+package com.unibus.app.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.automirrored.filled.Send
+import androidx.compose.material.icons.filled.AttachFile
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Tag
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.unibus.app.data.Message
+import com.unibus.app.data.Room
+import com.unibus.app.ui.theme.Brand3
+import com.unibus.app.ui.theme.LocalUnibusColors
+
+@Composable
+fun ChatScreen(
+    room: Room,
+    messages: List<Message>,
+    onSend: (String) -> Unit,
+    onBack: () -> Unit,
+) {
+    val colors = LocalUnibusColors.current
+    var draft by remember { mutableStateOf("") }
+    val listState = rememberLazyListState()
+
+    LaunchedEffect(messages.size, room.id) {
+        if (messages.isNotEmpty()) listState.animateScrollToItem(messages.size - 1)
+    }
+
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .background(colors.chatBg),
+    ) {
+        // Header
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 6.dp, vertical = 8.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            IconButton(onClick = onBack) {
+                Icon(Icons.AutoMirrored.Filled.ArrowBack, contentDescription = "Atrás", tint = Color.White)
+            }
+            InitialsAvatar(room.name, size = 38.dp, rounded = true, accent = true)
+            Column(
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(start = 10.dp),
+            ) {
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    Text(
+                        room.name,
+                        fontWeight = FontWeight(650),
+                        fontSize = 16.sp,
+                        color = Color.White,
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis,
+                    )
+                    Icon(
+                        if (room.encrypted) Icons.Filled.Lock else Icons.Filled.Tag,
+                        contentDescription = null,
+                        tint = colors.dimmed,
+                        modifier = Modifier
+                            .padding(start = 6.dp)
+                            .size(14.dp),
+                    )
+                }
+                Text(
+                    if (room.encrypted) "cifrada · E2E" else "abierta · cleartext",
+                    color = colors.dimmed,
+                    fontSize = 11.sp,
+                )
+            }
+            IconButton(onClick = { /* opciones de room (futuro) */ }) {
+                Icon(Icons.Filled.MoreVert, contentDescription = "Opciones", tint = colors.dimmed)
+            }
+        }
+        HorizontalDivider(color = colors.divider)
+
+        // Mensajes
+        LazyColumn(
+            state = listState,
+            modifier = Modifier
+                .weight(1f)
+                .fillMaxWidth(),
+            contentPadding = androidx.compose.foundation.layout.PaddingValues(14.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            items(messages, key = { it.id }) { msg -> MessageRow(msg) }
+        }
+
+        HorizontalDivider(color = colors.divider)
+
+        // Composer
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(8.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            IconButton(onClick = { /* adjuntar (futuro) */ }) {
+                Icon(Icons.Filled.AttachFile, contentDescription = "Adjuntar", tint = colors.dimmed)
+            }
+            OutlinedTextField(
+                value = draft,
+                onValueChange = { draft = it },
+                placeholder = { Text("Mensaje a ${room.name}") },
+                singleLine = true,
+                shape = CircleShape,
+                colors = TextFieldDefaults.colors(
+                    focusedContainerColor = colors.field,
+                    unfocusedContainerColor = colors.field,
+                ),
+                modifier = Modifier.weight(1f),
+                keyboardOptions = KeyboardOptions(imeAction = androidx.compose.ui.text.input.ImeAction.Send),
+                keyboardActions = KeyboardActions(onSend = {
+                    if (draft.trim().isNotEmpty()) { onSend(draft); draft = "" }
+                }),
+            )
+            Box(
+                modifier = Modifier
+                    .padding(start = 6.dp)
+                    .size(46.dp)
+                    .clip(CircleShape)
+                    .background(if (draft.trim().isEmpty()) colors.field else colors.brand),
+                contentAlignment = Alignment.Center,
+            ) {
+                IconButton(
+                    onClick = { if (draft.trim().isNotEmpty()) { onSend(draft); draft = "" } },
+                    enabled = draft.trim().isNotEmpty(),
+                ) {
+                    Icon(Icons.AutoMirrored.Filled.Send, contentDescription = "Enviar", tint = Color.White)
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun MessageRow(msg: Message) {
+    val colors = LocalUnibusColors.current
+    Row(verticalAlignment = Alignment.Top) {
+        InitialsAvatar(msg.sender, size = 36.dp, rounded = false, accent = msg.mine)
+        Column(modifier = Modifier.padding(start = 10.dp)) {
+            Row(verticalAlignment = Alignment.Bottom) {
+                Text(
+                    msg.sender,
+                    fontWeight = FontWeight.SemiBold,
+                    fontSize = 14.sp,
+                    color = if (msg.mine) Brand3 else Color.White,
+                )
+                Text(
+                    timeShort(msg.ts),
+                    color = colors.dimmed,
+                    fontSize = 11.sp,
+                    modifier = Modifier.padding(start = 8.dp),
+                )
+            }
+            Text(
+                msg.body,
+                fontSize = 14.sp,
+                color = com.unibus.app.ui.theme.OnSurface,
+                modifier = Modifier.padding(top = 1.dp),
+            )
+        }
+    }
+}

android/app/src/main/java/com/unibus/app/ui/Components.kt

@@ -0,0 +1,48 @@
+package com.unibus.app.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.unibus.app.ui.theme.Brand5
+
+/**
+ * Avatar con iniciales, equivalente al <Avatar> de la web. [rounded] = esquinas
+ * (rooms/chat header) vs círculo (usuarios). [accent] colorea el de marca.
+ */
+@Composable
+fun InitialsAvatar(
+    text: String,
+    size: Dp = 42.dp,
+    rounded: Boolean = true,
+    accent: Boolean = false,
+    modifier: Modifier = Modifier,
+) {
+    val shape = if (rounded) RoundedCornerShape((size.value * 0.28f).dp) else CircleShape
+    val bg = if (accent) Brand5 else Color(0xFF3A3D44) // gris neutro tipo Avatar color="gray"
+    Box(
+        modifier = modifier
+            .size(size)
+            .clip(shape)
+            .background(bg),
+        contentAlignment = Alignment.Center,
+    ) {
+        Text(
+            text = initials(text),
+            color = Color.White,
+            fontWeight = FontWeight.SemiBold,
+            fontSize = (size.value * 0.36f).sp,
+        )
+    }
+}

android/app/src/main/java/com/unibus/app/ui/LoginScreen.kt

@@ -0,0 +1,154 @@
+package com.unibus.app.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.VpnKey
+import androidx.compose.material3.Button
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.Icon
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.unibus.app.ui.theme.Brand4
+import com.unibus.app.ui.theme.Dark7
+import com.unibus.app.ui.theme.Dark9
+import com.unibus.app.ui.theme.LocalUnibusColors
+
+@Composable
+fun LoginScreen(
+    connecting: Boolean,
+    error: String?,
+    onLogin: (handle: String, password: String) -> Unit,
+) {
+    val colors = LocalUnibusColors.current
+    var handle by remember { mutableStateOf("") }
+    var password by remember { mutableStateOf("") }
+    val ready = handle.trim().isNotEmpty() && password.isNotEmpty() && !connecting
+
+    fun submit() {
+        if (ready) onLogin(handle.trim(), password)
+    }
+
+    Box(
+        modifier = Modifier
+            .fillMaxSize()
+            .background(Dark9),
+        contentAlignment = Alignment.Center,
+    ) {
+        Card(
+            modifier = Modifier
+                .padding(24.dp)
+                .fillMaxWidth(),
+            colors = CardDefaults.cardColors(containerColor = Dark7),
+            shape = androidx.compose.foundation.shape.RoundedCornerShape(16.dp),
+        ) {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(28.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(18.dp),
+            ) {
+                // ThemeIcon "light brand" — círculo translúcido con candado.
+                Box(
+                    modifier = Modifier
+                        .size(60.dp)
+                        .clip(CircleShape)
+                        .background(Brand4.copy(alpha = 0.18f)),
+                    contentAlignment = Alignment.Center,
+                ) {
+                    Icon(
+                        Icons.Filled.Lock,
+                        contentDescription = null,
+                        tint = Brand4,
+                        modifier = Modifier.size(30.dp),
+                    )
+                }
+
+                Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                    Text("unibus", fontSize = 26.sp, color = Brand4)
+                    Text(
+                        "Mensajería cifrada de extremo a extremo",
+                        color = colors.dimmed,
+                        fontSize = 13.sp,
+                        textAlign = TextAlign.Center,
+                    )
+                }
+
+                OutlinedTextField(
+                    value = handle,
+                    onValueChange = { handle = it },
+                    label = { Text("Identidad") },
+                    placeholder = { Text("tu-handle") },
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth(),
+                    keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next),
+                )
+
+                OutlinedTextField(
+                    value = password,
+                    onValueChange = { password = it },
+                    label = { Text("Contraseña") },
+                    placeholder = { Text("••••••••") },
+                    singleLine = true,
+                    visualTransformation = PasswordVisualTransformation(),
+                    leadingIcon = { Icon(Icons.Filled.VpnKey, contentDescription = null) },
+                    modifier = Modifier.fillMaxWidth(),
+                    keyboardOptions = KeyboardOptions(imeAction = ImeAction.Go),
+                    keyboardActions = KeyboardActions(onGo = { submit() }),
+                )
+                Text(
+                    "Desbloquea tu identidad cifrada en este dispositivo",
+                    color = colors.dimmed,
+                    fontSize = 12.sp,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+
+                if (error != null) {
+                    Text(error, color = androidx.compose.ui.graphics.Color(0xFFFF6B6B), fontSize = 13.sp)
+                }
+
+                Button(
+                    onClick = { submit() },
+                    enabled = ready,
+                    modifier = Modifier.fillMaxWidth(),
+                ) {
+                    if (connecting) {
+                        CircularProgressIndicator(
+                            modifier = Modifier.size(18.dp),
+                            strokeWidth = 2.dp,
+                            color = androidx.compose.ui.graphics.Color.White,
+                        )
+                    } else {
+                        Text("Conectar")
+                    }
+                }
+            }
+        }
+    }
+}

android/app/src/main/java/com/unibus/app/ui/RoomListScreen.kt

@@ -0,0 +1,199 @@
+package com.unibus.app.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.Logout
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material.icons.filled.Tag
+import androidx.compose.material3.Badge
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.unibus.app.data.Room
+import com.unibus.app.data.User
+import com.unibus.app.ui.theme.LocalUnibusColors
+
+@Composable
+fun RoomListScreen(
+    user: User,
+    rooms: List<Room>,
+    onSelect: (String) -> Unit,
+    onLogout: () -> Unit,
+) {
+    val colors = LocalUnibusColors.current
+    var query by remember { mutableStateOf("") }
+    val q = query.trim().lowercase()
+    val filtered = if (q.isEmpty()) rooms else rooms.filter {
+        it.name.lowercase().contains(q) || it.messages.any { m -> m.body.lowercase().contains(q) }
+    }
+
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .background(colors.sidebarBg),
+    ) {
+        // Header: avatar + handle + menú
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 12.dp, vertical = 10.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            InitialsAvatar(user.handle, size = 36.dp, rounded = false, accent = true)
+            Text(
+                user.handle,
+                fontWeight = FontWeight.SemiBold,
+                fontSize = 15.sp,
+                color = Color.White,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(start = 10.dp),
+            )
+            var menuOpen by remember { mutableStateOf(false) }
+            Box {
+                IconButton(onClick = { menuOpen = true }) {
+                    Icon(Icons.Filled.MoreVert, contentDescription = "Menú", tint = colors.dimmed)
+                }
+                DropdownMenu(expanded = menuOpen, onDismissRequest = { menuOpen = false }) {
+                    DropdownMenuItem(
+                        text = { Text("Desconectar") },
+                        onClick = { menuOpen = false; onLogout() },
+                        leadingIcon = {
+                            Icon(Icons.AutoMirrored.Filled.Logout, contentDescription = null, modifier = Modifier.size(18.dp))
+                        },
+                    )
+                }
+            }
+        }
+
+        // Buscador
+        OutlinedTextField(
+            value = query,
+            onValueChange = { query = it },
+            placeholder = { Text("Buscar rooms, usuarios, mensajes…") },
+            leadingIcon = { Icon(Icons.Filled.Search, contentDescription = null, modifier = Modifier.size(18.dp)) },
+            singleLine = true,
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 12.dp, vertical = 4.dp),
+        )
+
+        HorizontalDivider(color = colors.divider)
+
+        if (filtered.isEmpty()) {
+            Text(
+                "Sin resultados",
+                color = colors.dimmed,
+                fontSize = 14.sp,
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(top = 24.dp),
+                textAlign = androidx.compose.ui.text.style.TextAlign.Center,
+            )
+        } else {
+            LazyColumn(
+                modifier = Modifier.fillMaxSize(),
+                contentPadding = androidx.compose.foundation.layout.PaddingValues(6.dp),
+                verticalArrangement = Arrangement.spacedBy(2.dp),
+            ) {
+                items(filtered, key = { it.id }) { room ->
+                    RoomItem(room = room, onClick = { onSelect(room.id) })
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun RoomItem(room: Room, onClick: () -> Unit) {
+    val colors = LocalUnibusColors.current
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clip(RoundedCornerShape(10.dp))
+            .clickable(onClick = onClick)
+            .padding(8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        InitialsAvatar(room.name, size = 46.dp, rounded = true)
+        Column(
+            modifier = Modifier
+                .weight(1f)
+                .padding(start = 10.dp),
+        ) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Icon(
+                    if (room.encrypted) Icons.Filled.Lock else Icons.Filled.Tag,
+                    contentDescription = if (room.encrypted) "cifrada" else "abierta",
+                    tint = colors.dimmed,
+                    modifier = Modifier.size(13.dp),
+                )
+                Text(
+                    room.name,
+                    fontWeight = FontWeight.SemiBold,
+                    fontSize = 14.sp,
+                    color = Color.White,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier
+                        .weight(1f)
+                        .padding(start = 4.dp),
+                )
+                Text(timeShort(room.lastTs), color = colors.dimmed, fontSize = 11.sp)
+            }
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(top = 2.dp),
+            ) {
+                Text(
+                    room.lastMessage,
+                    color = colors.dimmed,
+                    fontSize = 12.sp,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.weight(1f),
+                )
+                if (room.unread > 0) {
+                    Badge(
+                        containerColor = colors.brand,
+                        contentColor = Color.White,
+                    ) { Text(room.unread.toString()) }
+                }
+            }
+        }
+    }
+}

android/app/src/main/java/com/unibus/app/ui/Util.kt

@@ -0,0 +1,17 @@
+package com.unibus.app.ui
+
+import java.util.Calendar
+
+/** Iniciales (hasta 2 letras/dígitos) para los avatares, igual que la web. */
+fun initials(s: String): String {
+    val cleaned = s.filter { it.isLetterOrDigit() }
+    return if (cleaned.isEmpty()) "?" else cleaned.take(2).uppercase()
+}
+
+/** Hora corta HH:mm a partir de epoch ms. */
+fun timeShort(ts: Long): String {
+    val c = Calendar.getInstance().apply { timeInMillis = ts }
+    val h = c.get(Calendar.HOUR_OF_DAY).toString().padStart(2, '0')
+    val min = c.get(Calendar.MINUTE).toString().padStart(2, '0')
+    return "$h:$min"
+}

android/app/src/main/java/com/unibus/app/ui/theme/Theme.kt

@@ -0,0 +1,80 @@
+package com.unibus.app.ui.theme
+
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Typography
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.sp
+
+// --- Brand: índigo/violeta de unibus (mismos tonos que el tema Mantine de la web) ---
+val Brand2 = Color(0xFFB5A3F5) // brand.2
+val Brand3 = Color(0xFF8D70ED) // brand.3 — legible sobre fondo oscuro
+val Brand4 = Color(0xFF6C47E6) // brand.4 — acento principal
+val Brand5 = Color(0xFF5A2FE2) // brand.5 — filled
+
+// --- Grises oscuros equivalentes a la escala dark.* de Mantine ---
+val Dark9 = Color(0xFF101113) // fondo de la app (login)
+val Dark8 = Color(0xFF141517) // sidebar / lista de rooms
+val Dark7 = Color(0xFF1A1B1E) // panel de chat / superficie
+val Dark6 = Color(0xFF25262B) // item activo / elevado
+val Dark5 = Color(0xFF2C2E33) // campos de entrada
+val Dark4 = Color(0xFF373A40) // bordes / divisores
+val Dimmed = Color(0xFF909296) // texto secundario
+val OnSurface = Color(0xFFE3E3E6) // texto principal
+
+/**
+ * Tokens de color que Material 3 no expresa directamente y que la UI replica de
+ * la web (matices dark.6/7/8/9, color "dimmed", borde). Se exponen vía un
+ * CompositionLocal para que cualquier composable los lea sin prop-drilling.
+ */
+data class UnibusColors(
+    val appBg: Color = Dark9,
+    val sidebarBg: Color = Dark8,
+    val chatBg: Color = Dark7,
+    val activeItem: Color = Dark6,
+    val field: Color = Dark5,
+    val divider: Color = Dark4,
+    val dimmed: Color = Dimmed,
+    val brand: Color = Brand4,
+)
+
+val LocalUnibusColors = staticCompositionLocalOf { UnibusColors() }
+
+private val UnibusDarkScheme = darkColorScheme(
+    primary = Brand4,
+    onPrimary = Color.White,
+    primaryContainer = Brand5,
+    onPrimaryContainer = Color.White,
+    secondary = Brand3,
+    background = Dark9,
+    onBackground = OnSurface,
+    surface = Dark7,
+    onSurface = OnSurface,
+    surfaceVariant = Dark6,
+    onSurfaceVariant = Dimmed,
+    outline = Dark4,
+    error = Color(0xFFFF6B6B),
+)
+
+private val UnibusTypography = Typography(
+    titleLarge = Typography().titleLarge.copy(fontWeight = FontWeight(650)),
+    titleMedium = Typography().titleMedium.copy(fontWeight = FontWeight(650)),
+    bodyMedium = Typography().bodyMedium.copy(fontSize = 14.sp),
+    labelLarge = Typography().labelLarge.copy(fontWeight = FontWeight.SemiBold),
+)
+
+@Composable
+fun UnibusTheme(content: @Composable () -> Unit) {
+    // unibus es dark-first; ignoramos el modo del sistema a propósito.
+    @Suppress("UNUSED_EXPRESSION")
+    isSystemInDarkTheme()
+    MaterialTheme(
+        colorScheme = UnibusDarkScheme,
+        typography = UnibusTypography,
+        content = content,
+    )
+}

android/app/src/main/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <!-- Material "lock" glyph, white, centered in the adaptive-icon safe zone.
+         24dp source scaled x3 (=72dp) and translated by 18 to center it. -->
+    <group
+        android:scaleX="3"
+        android:scaleY="3"
+        android:translateX="18"
+        android:translateY="18">
+        <path
+            android:fillColor="#FFFFFF"
+            android:pathData="M12,17c1.1,0 2,-0.9 2,-2s-0.9,-2 -2,-2 -2,0.9 -2,2 0.9,2 2,2zM18,8h-1V6c0,-2.76 -2.24,-5 -5,-5S7,3.24 7,6v2H6c-1.1,0 -2,0.9 -2,2v10c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2V10c0,-1.1 -0.9,-2 -2,-2zM9,6c0,-1.66 1.34,-3 3,-3s3,1.34 3,3v2H9V6z" />
+    </group>
+</vector>

android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/unibus_brand" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

android/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/unibus_brand" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

android/app/src/main/res/values/colors.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- dark.9 — app background -->
+    <color name="unibus_bg">#101113</color>
+    <!-- brand.5 — índigo/violeta accent, used as launcher icon background -->
+    <color name="unibus_brand">#5A2FE2</color>
+</resources>

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">unibus</string>
+</resources>

android/app/src/main/res/values/themes.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Compose-only host theme: no action bar, dark window background matching
+         the app's dark.9 surface so there is no white flash before Compose draws. -->
+    <style name="Theme.Unibus" parent="android:Theme.Material.NoActionBar">
+        <item name="android:windowBackground">@color/unibus_bg</item>
+        <item name="android:statusBarColor">@color/unibus_bg</item>
+        <item name="android:navigationBarColor">@color/unibus_bg</item>
+        <item name="android:windowLightStatusBar">false</item>
+    </style>
+</resources>

android/build.gradle.kts

@@ -0,0 +1,5 @@
+plugins {
+    id("com.android.application") version "8.5.2" apply false
+    id("org.jetbrains.kotlin.android") version "1.9.24" apply false
+    id("org.jetbrains.kotlin.plugin.serialization") version "1.9.24" apply false
+}

android/gradle.properties

@@ -0,0 +1,5 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+android.useAndroidX=true
+android.nonTransitiveRClass=true
+kotlin.code.style=official
+org.gradle.caching=true

android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

android/gradlew

@@ -0,0 +1,249 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

android/gradlew.bat

@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

android/settings.gradle.kts

@@ -0,0 +1,24 @@
+pluginManagement {
+    repositories {
+        google {
+            content {
+                includeGroupByRegex("com\\.android.*")
+                includeGroupByRegex("com\\.google.*")
+                includeGroupByRegex("androidx.*")
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "unibus"
+include(":app")

mobile/gen_aar.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+# Regenera el binding gomobile (unibus.aar) a partir de ./mobile sobre pkg/client.
+#
+# El .aar (~38 MB, con libgojni.so para 4 ABIs) NO se versiona: es un artefacto
+# de build reproducible. Este script lo regenera. Requisitos:
+#   - Go con gomobile/gobind instalados:
+#       go install golang.org/x/mobile/cmd/gomobile@latest
+#       go install golang.org/x/mobile/cmd/gobind@latest
+#       gomobile init
+#   - Android NDK (este repo usó 26.3.11579264 dentro del Android SDK).
+#
+# En un worktree fuera del árbol del registry, pkg/client importa
+# "fn-registry/functions/cybersecurity" vía el `replace` del go.mod. Si ese
+# replace relativo no resuelve (p. ej. worktree en /tmp), crea un go.work local
+# (gitignored) con: replace fn-registry => /ruta/absoluta/a/fn_registry
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+: "${ANDROID_HOME:=$HOME/android-sdk}"
+: "${ANDROID_NDK_HOME:=$ANDROID_HOME/ndk/26.3.11579264}"
+export ANDROID_HOME ANDROID_NDK_HOME
+export PATH="$HOME/go/bin:$PATH"
+
+OUT="android/app/libs/unibus.aar"
+mkdir -p "$(dirname "$OUT")"
+
+echo "==> gomobile bind -> $OUT"
+gomobile bind \
+  -target=android \
+  -androidapi 21 \
+  -javapkg com.unibus.core \
+  -o "$OUT" \
+  ./mobile
+
+echo "==> OK: $OUT"
+ls -lh "$OUT"

mobile/unibus.go

@@ -0,0 +1,236 @@
+// Package mobile exposes a flat, gomobile-friendly API over the unibus client
+// so an Android app can join rooms, publish, and receive messages with the same
+// end-to-end encryption as any native Go peer.
+//
+// gomobile only supports a limited set of types across the binding boundary
+// (string, []byte, int, bool, error, named structs, and interfaces). This layer
+// translates the richer client API into those primitives and delivers incoming
+// frames through a Java/Kotlin-implemented FrameListener callback. No protocol
+// or cryptography is reimplemented here: every call delegates to pkg/client,
+// which is the single source of truth shared with every other peer on the bus.
+package mobile
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/enmanuel/unibus/pkg/client"
+	"github.com/enmanuel/unibus/pkg/frame"
+	"github.com/enmanuel/unibus/pkg/room"
+)
+
+// FrameListener receives decrypted messages for a subscribed room. The Android
+// side implements this interface.
+//
+// IMPORTANT (threading): OnFrame is invoked from a NATS delivery goroutine, NOT
+// the Android main thread. A Kotlin implementation MUST hop back to the UI
+// thread before touching any Compose state or Android view — for example with
+// `withContext(Dispatchers.Main)` from a coroutine, or by posting to a
+// MutableStateFlow that the UI collects. Touching views directly from here
+// crashes with CalledFromWrongThreadException.
+type FrameListener interface {
+	OnFrame(roomID string, sender string, msgID string, text string)
+}
+
+// Session is a connected unibus peer. Create it with NewSession and close it
+// with Close when the app stops.
+type Session struct {
+	c *client.Client
+}
+
+// GenerateIdentity creates (or loads) the long-term keypair stored at path.
+// Call it once on first launch. The resulting file holds the peer's private
+// Ed25519 and X25519 keys and must be kept private to the app sandbox
+// (use Context.getFilesDir() on Android).
+func GenerateIdentity(path string) error {
+	_, err := client.LoadOrCreateIdentity(path)
+	return err
+}
+
+// NewSession loads the identity at idPath and connects to the bus. natsURL is
+// the data plane (for example tls://host:4250) and ctrlURL is the control plane
+// HTTP endpoint (for example https://host:8470). caPath is the path to the bus
+// CA certificate (ca.crt) bundled with the app: when set, the session connects
+// securely (TLS pinned to that CA + nkey authentication on the data plane),
+// matching a bus running with auth + TLS. Pass an empty caPath to connect in
+// plaintext to an unsecured (dev) bus.
+func NewSession(idPath, natsURL, ctrlURL, caPath string) (*Session, error) {
+	id, err := client.LoadOrCreateIdentity(idPath)
+	if err != nil {
+		return nil, err
+	}
+	c, err := client.Connect(natsURL, ctrlURL, id, caPath)
+	if err != nil {
+		return nil, err
+	}
+	return &Session{c: c}, nil
+}
+
+// EndpointID returns this peer's stable endpoint identifier, derived from its
+// signing public key. It is the value that appears as the sender of frames.
+func (s *Session) EndpointID() string {
+	return s.c.Endpoint().ID
+}
+
+// ConnectedServer returns the NATS URL the session is currently connected to,
+// useful for surfacing a "connected to" hint in the UI.
+func (s *Session) ConnectedServer() string {
+	return s.c.ConnectedServer()
+}
+
+// IsConnected reports whether the underlying NATS connection is live.
+func (s *Session) IsConnected() bool {
+	return s.c.IsConnected()
+}
+
+// CreateRoom opens a room on the given subject. mode is "matrix" for the
+// encrypted, persisted and signed policy, or "nats" for plain cleartext. It
+// returns the room id used by Join, Publish and Subscribe.
+//
+// On a secured bus, call RefreshSession after CreateRoom and before
+// Subscribe/Publish so the bus re-derives this peer's per-subject permissions
+// from its new membership (issue 0006e).
+func (s *Session) CreateRoom(subject, mode string) (string, error) {
+	p := room.ModeNATS
+	if mode == "matrix" {
+		p = room.ModeMatrix
+	}
+	return s.c.CreateRoom(subject, p)
+}
+
+// Join fetches the room key when the room is encrypted and prepares the session
+// to publish to and receive from the room.
+func (s *Session) Join(roomID string) error {
+	return s.c.Join(roomID)
+}
+
+// RefreshSession reconnects the data plane so the bus re-derives this peer's
+// per-subject permissions from its current room membership.
+//
+// Membership-change contract (issue 0006e): a secured bus (--bus-auth enforce)
+// freezes a connection's permissions at connect time. After ANY membership change
+// — a room you just created, were invited to, or joined — call RefreshSession
+// BEFORE Publish/Subscribe on that room, or the bus denies the new room's subject.
+// It also drops active subscriptions, so re-Subscribe afterwards. On an unsecured
+// bus it is a harmless reconnect. A mobile/gateway caller wires this exactly like
+// cmd/chat and cmd/worker do: CreateRoom -> RefreshSession -> Subscribe/Publish.
+func (s *Session) RefreshSession() error {
+	return s.c.RefreshSession()
+}
+
+// Publish sends a UTF-8 text message to the room.
+func (s *Session) Publish(roomID, text string) error {
+	return s.c.Publish(roomID, []byte(text))
+}
+
+// Subscribe streams decrypted messages of the room to the listener until the
+// session is closed. See FrameListener for the threading contract.
+func (s *Session) Subscribe(roomID string, l FrameListener) error {
+	_, err := s.c.Subscribe(roomID, func(f frame.Frame, plaintext []byte) {
+		l.OnFrame(roomID, f.Sender, f.MsgID, string(plaintext))
+	})
+	return err
+}
+
+// roomJSON is the flat shape returned by ListRoomsJSON for each room the peer
+// belongs to. It mirrors the fields the UI needs to render a room list item.
+type roomJSON struct {
+	RoomID    string `json:"room_id"`
+	Subject   string `json:"subject"`
+	Epoch     int    `json:"epoch"`
+	Encrypted bool   `json:"encrypted"`
+	Role      string `json:"role"`
+}
+
+// ListRoomsJSON returns the peer's rooms as a JSON array string. gomobile does
+// not bind slices of structs cleanly across the boundary, so the list is
+// marshalled to JSON and the Kotlin side decodes it (kotlinx.serialization).
+// Each element is a roomJSON object.
+func (s *Session) ListRoomsJSON() (string, error) {
+	refs, err := s.c.ListMyRooms()
+	if err != nil {
+		return "", err
+	}
+	out := make([]roomJSON, 0, len(refs))
+	for _, r := range refs {
+		out = append(out, roomJSON{
+			RoomID:    r.RoomID,
+			Subject:   r.Subject,
+			Epoch:     r.Epoch,
+			Encrypted: r.Policy.Encrypt,
+			Role:      r.Role,
+		})
+	}
+	b, err := json.Marshal(out)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+// cardJSON is the portable, copy-pasteable public identity a peer shares so a
+// room owner can invite it to an encrypted room. It carries no secret: only the
+// endpoint id and the two public keys (signing + key-exchange), base64-encoded
+// for transport over text or a QR code.
+type cardJSON struct {
+	ID      string `json:"id"`
+	SignPub string `json:"sign_pub"` // base64 std of the Ed25519 public key
+	KexPub  string `json:"kex_pub"`  // base64 std of the X25519 public key
+}
+
+// Card returns this peer's public identity as a portable JSON string. Share it
+// (paste, QR) with a room owner so they can Invite you to an encrypted room. It
+// contains no private key and is safe to transmit in the clear.
+func (s *Session) Card() string {
+	ep := s.c.Endpoint()
+	b, _ := json.Marshal(cardJSON{
+		ID:      ep.ID,
+		SignPub: base64.StdEncoding.EncodeToString(ep.SignPub),
+		KexPub:  base64.StdEncoding.EncodeToString(ep.KexPub),
+	})
+	return string(b)
+}
+
+// Invite adds the holder of peerCard to roomID. peerCard is the JSON string the
+// invitee produced with Card(). For encrypted rooms this seals the current room
+// key to the invitee's X25519 public key and signs the request; the caller must
+// be the room owner.
+func (s *Session) Invite(roomID, peerCard string) error {
+	var card cardJSON
+	if err := json.Unmarshal([]byte(peerCard), &card); err != nil {
+		return fmt.Errorf("mobile: bad peer card: %w", err)
+	}
+	signPub, err := base64.StdEncoding.DecodeString(card.SignPub)
+	if err != nil {
+		return fmt.Errorf("mobile: bad sign_pub in card: %w", err)
+	}
+	kexPub, err := base64.StdEncoding.DecodeString(card.KexPub)
+	if err != nil {
+		return fmt.Errorf("mobile: bad kex_pub in card: %w", err)
+	}
+	return s.c.Invite(roomID, client.Endpoint{ID: card.ID, SignPub: signPub, KexPub: kexPub})
+}
+
+// Kick removes endpointID from roomID and, for encrypted rooms, rotates the room
+// key to a new epoch so the removed peer cannot decrypt messages published after
+// the kick (forward secrecy). The caller must be the room owner.
+func (s *Session) Kick(roomID, endpointID string) error {
+	return s.c.Kick(roomID, endpointID)
+}
+
+// Request performs an RPC request/reply against subject and returns the reply
+// payload as text. timeoutMs bounds the wait in milliseconds.
+func (s *Session) Request(subject, text string, timeoutMs int) (string, error) {
+	out, err := s.c.Request(subject, []byte(text), time.Duration(timeoutMs)*time.Millisecond)
+	if err != nil {
+		return "", err
+	}
+	return string(out), nil
+}
+
+// Close disconnects the peer from the bus.
+func (s *Session) Close() error {
+	return s.c.Close()
+}