Share what's playing in any Android music app

A local Expo module listens to system media sessions (the only way
Android exposes other apps' playback, gated by notification access; we
never read notifications). It filters to known music apps, debounces and
deduplicates changes, sends a heartbeat while playing, and delivers
reports through WorkManager so they survive the app being closed.

- One-screen onboarding that doubles as Google Play's prominent
  disclosure, opening straight to the app's toggle in Android settings
- Only media notifications are pre-ticked on that settings screen
- Device registration is single-flight (several screens react to the
  same permission change) and self-heals if the server revokes a token
- Sign-out revokes the phone's token; resuming sharing re-sends the
  current track immediately
- Pause controls in Settings and on the feed
- Fix invisible tab icons and labels on Android
- Keep Metro out of build output so it doesn't exhaust file watchers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/mobile/metro.config.js

@@ -0,0 +1,20 @@
+// https://docs.expo.dev/guides/customizing-metro/
+const { getDefaultConfig } = require('expo/metro-config');
+
+const config = getDefaultConfig(__dirname);
+
+// Metro watches the whole monorepo. Keep it out of build output (Gradle, Xcode,
+// Next.js, tsup): those folders hold tens of thousands of files, and exhausting
+// the OS file-watch limit makes Metro silently stop picking up code changes.
+const buildOutput = [
+  /[/\\]apps[/\\]mobile[/\\]android[/\\]/,
+  /[/\\]apps[/\\]mobile[/\\]ios[/\\]/,
+  /[/\\]modules[/\\][^/\\]+[/\\]android[/\\]build[/\\]/,
+  /[/\\]apps[/\\]web[/\\]\.next[/\\]/,
+  /[/\\]apps[/\\]api[/\\]dist[/\\]/,
+  /[/\\]\.turbo[/\\]/,
+];
+const existing = config.resolver.blockList;
+config.resolver.blockList = [...(Array.isArray(existing) ? existing : existing ? [existing] : []), ...buildOutput];
+
+module.exports = config;