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/android/app/google-services.json

@@ -0,0 +1,29 @@
+{
+  "project_info": {
+    "project_number": "1068156046511",
+    "project_id": "halobestie-clone-dev",
+    "storage_bucket": "halobestie-clone-dev.firebasestorage.app"
+  },
+  "client": [
+    {
+      "client_info": {
+        "mobilesdk_app_id": "1:1068156046511:android:ba6e699216de1c50b8185a",
+        "android_client_info": {
+          "package_name": "com.halobestie.client.client_app"
+        }
+      },
+      "oauth_client": [],
+      "api_key": [
+        {
+          "current_key": "AIzaSyDFWlLSWytqwI7LSdUbVrO7J5De9L2LV2U"
+        }
+      ],
+      "services": {
+        "appinvite_service": {
+          "other_platform_oauth_client": []
+        }
+      }
+    }
+  ],
+  "configuration_version": "1"
+}