feat: Android Compose client for the unibus bus

Thin Jetpack Compose UI over the real Go client (pkg/client) compiled to a
gomobile .aar, so the phone speaks NATS and runs the same end-to-end crypto as
any other peer. Connect, create room (nats/matrix), publish and live-receive.

.gitignore

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+.gradle/
+build/
+local.properties
+*.iml
+.idea/
+captures/
+.externalNativeBuild/
+.cxx/
+*.apk
+*.aab
+# NOTE: app/src/test/snapshots/ is committed (Roborazzi goldens are test refs).

README.md

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+# gallery_kt
+
+Showcase galeria de todos los componentes @fn_compose en diferentes estados
+
+Generado con `init_kotlin_app` del registry fn_registry.
+
+## Requisitos
+
+- Android SDK 34
+- JDK 17
+- Gradle 8.6 (via wrapper)
+- `kotlin/functions/ui` modulo del registry (composite build)
+
+## Build rapido
+
+```bash
+fn run gradle_assemble_debug_bash_infra apps/gallery_kt
+```

app.md

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+---
+name: unibus_android
+domain: tools
+version: 0.1.0
+description: "Cliente Android (Jetpack Compose) del bus unibus: conecta, crea salas y chatea con el mismo cliente Go (pkg/client) compilado a un .aar via gomobile, conservando el cifrado E2E."
+tags: [messaging, nats, e2e, android, compose, kotlin, gomobile, client]
+lang: kt
+framework: compose
+entry_point: "app/src/main/kotlin/com/fnregistry/unibus/MainActivity.kt"
+dir_path: "projects/message_bus/apps/unibus_android"
+repo_url: "https://gitea.organic-machine.com/dataforge/unibus_android"
+uses_functions:
+  - fn_theme_kt_ui
+  - fn_tokens_kt_ui
+  - fn_stack_kt_ui
+  - fn_group_kt_ui
+  - fn_card_kt_ui
+  - fn_badge_kt_ui
+  - fn_button_kt_ui
+  - fn_text_kt_ui
+  - fn_title_kt_ui
+  - fn_text_input_kt_ui
+  - fn_switch_kt_ui
+uses_types: []
+e2e_checks:
+  - id: bind
+    cmd: "cd ../unibus && gomobile bind -target=android -androidapi 24 -o ../unibus_android/app/libs/unibus.aar github.com/enmanuel/unibus/mobile"
+    timeout_s: 600
+  - id: build
+    cmd: "fn run gradle_assemble_debug_bash_infra projects/message_bus/apps/unibus_android"
+    timeout_s: 360
+---
+
+# unibus_android
+
+Cliente Android del bus de mensajería `unibus`. La aplicación es una fina capa de
+interfaz en Jetpack Compose sobre el cliente Go real del bus: `pkg/client` se compila
+a una librería nativa Android (`unibus.aar`) con `gomobile bind`, de modo que el teléfono
+habla el protocolo NATS y ejecuta el mismo cifrado end-to-end (ChaCha20-Poly1305 +
+Ed25519 + X25519) que cualquier otro peer. No se reimplementa ni el protocolo ni la
+criptografía: hay una única fuente de verdad compartida con el resto del ecosistema.
+
+## Arquitectura
+
+```
+MainActivity.kt (Compose UI)
+   └── mobile.Session  (Kotlin, generado por gomobile)
+         └── unibus.aar  (libgojni.so: pkg/client + nats.go + crypto del registry)
+               ├── data plane  → NATS TCP        (nats://host:4250)
+               └── control plane → HTTP REST      (http://host:8470)
+```
+
+El wrapper Go que define la API plana del binding vive en
+`projects/message_bus/apps/unibus/mobile/unibus.go` (paquete `mobile`): expone
+`NewSession`, `CreateRoom`, `Join`, `Publish`, `Subscribe`, `Request` y la interfaz
+`FrameListener` con tipos compatibles con gomobile (string, []byte, int, error,
+interface).
+
+## Regenerar el binding (.aar)
+
+Tras tocar `pkg/client` o el wrapper `mobile/`:
+
+```bash
+cd projects/message_bus/apps/unibus
+export ANDROID_HOME=$HOME/android-sdk
+export ANDROID_NDK_HOME=$(ls -d $HOME/android-sdk/ndk/* | head -1)
+export PATH="$PATH:$(go env GOPATH)/bin"
+gomobile bind -target=android -androidapi 24 \
+  -o ../unibus_android/app/libs/unibus.aar \
+  github.com/enmanuel/unibus/mobile
+```
+
+## Build del APK
+
+```bash
+fn run gradle_assemble_debug_bash_infra projects/message_bus/apps/unibus_android
+# o, directo:
+cd projects/message_bus/apps/unibus_android && ./gradlew :app:assembleDebug
+# salida: app/build/outputs/apk/debug/app-debug.apk
+```
+
+## Probarlo contra el bus
+
+1. Levantar el control plane real (NATS embebido + REST de membresía):
+   ```bash
+   cd projects/message_bus/apps/unibus
+   go run ./cmd/membershipd            # HTTP :8470, NATS :4250
+   ```
+2. En el **emulador** (`Pixel_API34`), instalar el APK. La app usa `host = 10.0.2.2`,
+   que el emulador mapea al loopback del PC, así que conecta sin más configuración.
+3. En la app: Conectar → Crear sala → escribir un mensaje. El mensaje viaja al bus por
+   NATS y vuelve al propio suscriptor (eco del subject), confirmando el camino completo
+   APK → bus → APK.
+
+## Gotchas
+
+- `cmd/membershipd` escucha en `127.0.0.1` (líneas `addr := "127.0.0.1:" + httpPort`).
+  Desde el emulador funciona (10.0.2.2 → loopback del host). Para un **teléfono real** en
+  la LAN o vía Tailscale hay que bindear el control plane y el NATS embebido a `0.0.0.0`
+  y usar la IP de red del PC/VPS en los campos Host de la app.
+- El control plane v1 es HTTP sin TLS; el manifest declara `usesCleartextTraffic="true"`.
+  Para producción, exponer el bus con TLS y quitar ese flag.
+- El `.aar` pesa ~24 MB (runtime Go embebido) y el APK debug ~54 MB. Es esperado: el
+  cliente Go completo viaja dentro.
+- `onFrame` del `FrameListener` llega en una goroutine de entrega de NATS; la UI hace
+  `Handler(mainLooper).post { ... }` antes de tocar el estado de Compose.
+
+## Capability growth log
+
+- v0.1.0 (2026-06-05) — baseline: conectar, crear sala (modo nats/matrix), publicar y
+  recibir mensajes en vivo. Binding gomobile del `pkg/client` con cifrado E2E intacto.

app/build.gradle.kts

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+plugins {
+    id("com.android.application") version "8.4.0"
+    id("org.jetbrains.kotlin.android") version "1.9.22"
+}
+
+android {
+    namespace = "com.fnregistry.unibus"
+    compileSdk = 34
+
+    defaultConfig {
+        applicationId = "com.fnregistry.unibus"
+        minSdk = 24
+        targetSdk = 34
+        versionCode = 1
+        versionName = "0.1.0"
+    }
+
+    buildFeatures {
+        compose = true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion = "1.5.8"
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    kotlinOptions {
+        jvmTarget = "17"
+    }
+}
+
+dependencies {
+    // unibus client compiled from Go via gomobile: holds the NATS data-plane
+    // connection, the HTTP control-plane calls and the end-to-end crypto. This is
+    // the same pkg/client every other peer uses, so the protocol has one source
+    // of truth.
+    implementation(files("libs/unibus.aar"))
+
+    implementation("androidx.activity:activity-compose:1.8.2")
+    implementation(platform("androidx.compose:compose-bom:2024.02.00"))
+    implementation("androidx.compose.ui:ui")
+    implementation("androidx.compose.material3:material3")
+    implementation("androidx.compose.ui:ui-tooling-preview")
+    debugImplementation("androidx.compose.ui:ui-tooling")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3")
+
+    // FnTheme + FnTokens via composite build
+    implementation("fn.compose:ui")
+}

app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- Data plane (NATS TCP) and control plane (HTTP) reach the bus over the network. -->
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:allowBackup="true"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:usesCleartextTraffic="true"
+        android:theme="@android:style/Theme.Material.Light.NoActionBar">
+
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

app/src/main/kotlin/com/fnregistry/unibus/MainActivity.kt

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+package com.fnregistry.unibus
+
+import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Surface
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateListOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import fn.compose.theme.FnSpacing
+import fn.compose.theme.FnTheme
+import fn.compose.ui.FnBadge
+import fn.compose.ui.FnBadgeColor
+import fn.compose.ui.FnButton
+import fn.compose.ui.FnButtonVariant
+import fn.compose.ui.FnCard
+import fn.compose.ui.FnGroup
+import fn.compose.ui.FnStack
+import fn.compose.ui.FnSwitch
+import fn.compose.ui.FnText
+import fn.compose.ui.FnTextInput
+import fn.compose.ui.FnTextSize
+import fn.compose.ui.FnTitle
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import mobile.FrameListener
+import mobile.Mobile
+import mobile.Session
+import java.io.File
+
+/**
+ * Single-activity chat client for the unibus message bus. The whole protocol —
+ * NATS data plane, HTTP control plane and end-to-end crypto — lives inside the
+ * gomobile-built unibus.aar (package `mobile`); this UI only orchestrates calls
+ * to a [Session] and renders the frames it delivers.
+ */
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // The long-term identity (Ed25519 + X25519 keys) is stored in the app's
+        // private files directory, unreadable by other apps.
+        val idPath = File(filesDir, "peer.id").absolutePath
+        setContent {
+            FnTheme {
+                Surface(Modifier.fillMaxSize()) {
+                    ChatApp(idPath)
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ChatApp(idPath: String) {
+    val scope = rememberCoroutineScope()
+    // onFrame arrives on a NATS delivery thread; hop to the main thread before
+    // touching Compose state.
+    val mainHandler = remember { Handler(Looper.getMainLooper()) }
+
+    // 10.0.2.2 is the host machine as seen from the Android emulator. On a real
+    // phone, replace it with the PC/VPS LAN or Tailscale address.
+    var host by remember { mutableStateOf("10.0.2.2") }
+    var natsPort by remember { mutableStateOf("4250") }
+    var ctrlPort by remember { mutableStateOf("8470") }
+    var subject by remember { mutableStateOf("room.general") }
+    var e2e by remember { mutableStateOf(false) }
+
+    var session by remember { mutableStateOf<Session?>(null) }
+    var roomId by remember { mutableStateOf<String?>(null) }
+    var status by remember { mutableStateOf("Desconectado") }
+    var draft by remember { mutableStateOf("") }
+    val messages = remember { mutableStateListOf<String>() }
+
+    val listener = remember {
+        object : FrameListener {
+            override fun onFrame(roomID: String, sender: String, msgID: String, text: String) {
+                mainHandler.post { messages.add("${sender.take(6)} › $text") }
+            }
+        }
+    }
+
+    FnStack(
+        modifier = Modifier.fillMaxSize().padding(FnSpacing.md),
+        gap = FnSpacing.sm,
+    ) {
+        FnTitle("Unibus", order = 2)
+        FnText(status, size = FnTextSize.Sm)
+
+        when {
+            // --- Step 1: connect to the bus ---
+            session == null -> {
+                FnTextInput(
+                    value = host,
+                    onValueChange = { host = it },
+                    label = "Host",
+                    placeholder = "10.0.2.2 / IP LAN / tailscale",
+                    modifier = Modifier.fillMaxWidth(),
+                )
+                FnGroup(gap = FnSpacing.sm) {
+                    FnTextInput(value = natsPort, onValueChange = { natsPort = it }, label = "NATS", modifier = Modifier.weight(1f))
+                    FnTextInput(value = ctrlPort, onValueChange = { ctrlPort = it }, label = "Control", modifier = Modifier.weight(1f))
+                }
+                FnButton("Conectar", onClick = {
+                    status = "Conectando…"
+                    scope.launch {
+                        try {
+                            val s = withContext(Dispatchers.IO) {
+                                Mobile.newSession(idPath, "nats://$host:$natsPort", "http://$host:$ctrlPort")
+                            }
+                            session = s
+                            status = "Conectado · ${s.endpointID().take(10)}"
+                        } catch (e: Exception) {
+                            status = "Error al conectar: ${e.message}"
+                        }
+                    }
+                }, modifier = Modifier.fillMaxWidth())
+            }
+
+            // --- Step 2: open a room ---
+            roomId == null -> {
+                FnTextInput(
+                    value = subject,
+                    onValueChange = { subject = it },
+                    label = "Subject de la sala",
+                    placeholder = "room.general",
+                    modifier = Modifier.fillMaxWidth(),
+                )
+                FnSwitch(checked = e2e, onCheckedChange = { e2e = it }, label = "Cifrado E2E (modo matrix)")
+                FnButton("Crear sala", onClick = {
+                    status = "Creando sala…"
+                    scope.launch {
+                        try {
+                            val mode = if (e2e) "matrix" else "nats"
+                            val rid = withContext(Dispatchers.IO) {
+                                val r = session!!.createRoom(subject, mode)
+                                session!!.join(r)
+                                session!!.subscribe(r, listener)
+                                r
+                            }
+                            roomId = rid
+                            status = "Sala activa"
+                        } catch (e: Exception) {
+                            status = "Error al crear sala: ${e.message}"
+                        }
+                    }
+                }, modifier = Modifier.fillMaxWidth())
+            }
+
+            // --- Step 3: chat ---
+            else -> {
+                FnGroup(gap = FnSpacing.sm) {
+                    FnBadge(if (e2e) "E2E" else "PLAIN", color = if (e2e) FnBadgeColor.Green else FnBadgeColor.Gray)
+                    FnText(subject, size = FnTextSize.Xs)
+                }
+                FnCard(modifier = Modifier.fillMaxWidth().weight(1f)) {
+                    FnStack(
+                        modifier = Modifier.fillMaxSize().verticalScroll(rememberScrollState()),
+                        gap = FnSpacing.xs,
+                    ) {
+                        if (messages.isEmpty()) {
+                            FnText("Sin mensajes todavía. Envía el primero.", size = FnTextSize.Sm)
+                        } else {
+                            messages.forEach { FnText(it, size = FnTextSize.Sm) }
+                        }
+                    }
+                }
+                FnGroup(gap = FnSpacing.sm) {
+                    FnTextInput(
+                        value = draft,
+                        onValueChange = { draft = it },
+                        label = "Mensaje",
+                        modifier = Modifier.weight(1f),
+                    )
+                    FnButton("Enviar", onClick = {
+                        val text = draft.trim()
+                        if (text.isEmpty()) return@FnButton
+                        draft = ""
+                        scope.launch {
+                            try {
+                                withContext(Dispatchers.IO) { session!!.publish(roomId!!, text) }
+                            } catch (e: Exception) {
+                                status = "Error al enviar: ${e.message}"
+                            }
+                        }
+                    }, variant = FnButtonVariant.Filled)
+                }
+            }
+        }
+    }
+}

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

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">Unibus</string>
+</resources>

build.gradle.kts

@@ -0,0 +1,5 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    id("com.android.application") version "8.4.0" apply false
+    id("org.jetbrains.kotlin.android") version "1.9.22" apply false
+}

gradle.properties

@@ -0,0 +1,4 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+android.useAndroidX=true
+kotlin.code.style=official
+android.nonTransitiveRClass=true

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,251 @@
+#!/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.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   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/platforms/jvm/plugins-application/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 -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || 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 "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH="\\\"\\\""
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$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, 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" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# 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 "$JAVACMD" "$@"

settings.gradle.kts

@@ -0,0 +1,24 @@
+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        google()
+        mavenCentral()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+rootProject.name = "unibus_android"
+include(":app")
+
+// Composite build: FnTheme + FnTokens design system from the registry (fn.compose:ui).
+// Path climbs apps/unibus_android -> apps -> message_bus -> projects -> fn_registry.
+includeBuild("../../../../kotlin/functions/ui") {
+    dependencySubstitution {
+        substitute(module("fn.compose:ui")).using(project(":"))
+    }
+}