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/.metadata

@@ -0,0 +1,45 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "3b62efc2a3da49882f43c372e0bc53daef7295a6"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: android
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: ios
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: linux
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: macos
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: web
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+    - platform: windows
+      create_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+      base_revision: 3b62efc2a3da49882f43c372e0bc53daef7295a6
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'