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.

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(":"))
+    }
+}