Dart consumer for the Android permission state pipeline. New
AndroidPermissionsService listens on the app.chanora/android_permissions
MethodChannel and exposes a ValueListenable for the UI. The voice-join
flow in main.dart calls ensureRecordAudio() before rust.voiceJoin and
clamps to listen-only via setHardMute on denial. A non-modal banner
above the VoiceBar surfaces the Grant / Open Settings action depending
on whether the state is Denied or PermanentlyDenied. On non-Android
hosts the service short-circuits to granted; the banner is never built.
Also adds the BackIntentService Dart consumer (back_intent_policy +
back_intent_service) which the Kotlin BackIntentBridge invokes via
MethodChannel for deterministic route-pop ordering.
Trace: SDD-028, SDD-106, SRS-163, SRS-209.
EdisonJwa
c4145a8727