feat(android): output picker foundation - mediarouter + OutputRoute

Bluetooth slice (1/5). Adds the androidx.mediarouter 1.7.0 dep,
declares BLUETOOTH_CONNECT (needed on Android 12+ to enumerate
paired BT devices by name), and lays down the OutputRoute domain
model.

OutputRoute decouples the picker UI from MediaRouter.RouteInfo
(framework class, can't be constructed in JVM tests - same
constraint we hit with LikeMediaCallback). The Protocol enum
includes UPNP/CAST/SONOS placeholders so the next slice slots in
without a data-model rename - see
docs/superpowers/specs/2026-06-03-android-output-picker-upnp-scope.md
for the deferred work.

Controller + ViewModel + Compose UI land in follow-up commits.

android/app/build.gradle.kts

@@ -173,6 +173,7 @@ dependencies {
     implementation(libs.media3.exoplayer)
     implementation(libs.media3.session)
     implementation(libs.media3.datasource.okhttp)
+    implementation(libs.mediarouter)
 
     implementation(libs.coil.compose)
     implementation(libs.coil.network.okhttp)