refactor: clean up 55 lint warnings and issues

- Remove all 31 avoid_print debug statements across codebase
- Fix 8 critical warnings (unused variables, unreachable defaults, etc)
- Update deprecated APIs: launch() → launchUrl(), textScaleFactor → textScaler
- Replace deprecated surfaceVariant → surfaceContainerHighest in Material 3 themes
- Refactor switch statements to use modern pattern matching
- Remove unused code: _showDialog, _initNoLocation, _getAnchorOffset
- Fix use_build_context_synchronously by adding mounted checks
- Add ignore_for_file annotations to generated JSON serialization files
- Fix type annotations in appState.dart and models

Warnings reduced from 301 to 246 issues (8 → 0 critical warnings).
Build verified: app-production-debug.apk (160MB) compiles successfully.
Zero type errors, Dart analysis clean for critical issues.

lib/activeFires.dart

@@ -189,7 +189,6 @@ class _ActiveFiresPageState extends State<ActiveFiresPage> {
     return StoreConnector<AppState, _ViewModel>(
         distinct: true,
         converter: (Store<AppState> store) {
-          print('New ViewModel of Active Fires');
           return _ViewModel(
               onAdd: (YourLocation loc) {
                 if (store.state.yourLocations.any(
@@ -229,7 +228,6 @@ class _ActiveFiresPageState extends State<ActiveFiresPage> {
           final String title = hasLocations
               ? S.of(context).firesInYourPlaces
               : S.of(context).firesInTheWorld;
-          print('Building Active Fires');
 
           return Scaffold(
             key: _scaffoldKey,