Phase 2 refinements: Firebase config, dev environment fixes, phase 3 requirement draft

- Integrated Firebase SDK in both Flutter apps (google-services, firebase_options)
- Fixed auth flow, API client, and pairing/status blocs for dev environment
- Added full Flutter project scaffolds (android, ios, web, etc.)
- Added phase 3 chat engine requirement document
- Added bugreport zip pattern to gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client_app/firebase.json

@@ -0,0 +1 @@
+{"flutter":{"platforms":{"android":{"default":{"projectId":"halobestie-clone-dev","appId":"1:1068156046511:android:ba6e699216de1c50b8185a","fileOutput":"android/app/google-services.json"}},"dart":{"lib/firebase_options.dart":{"projectId":"halobestie-clone-dev","configurations":{"android":"1:1068156046511:android:ba6e699216de1c50b8185a","ios":"1:1068156046511:ios:c7786cedb9101d34b8185a"}}}}}}