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/redux/fetchDataMiddleware.dart

@@ -156,12 +156,10 @@ void fetchDataMiddleware(
           .then((List<YourLocation> subscribedLocations) {
         // If it succeeds, dispatch a success action with the YourLocations.
         // Our reducer will then update the State using these YourLocations.
-        print('Subscribed to: ${subscribedLocations.length}');
         // unsubscribe all locally to sync the subs state
         for (final YourLocation location in localLocations) {
           location.subscribed = false;
         }
-        print('Local persisted: ${localLocations.length}');
         for (final YourLocation subsLoc in subscribedLocations) {
           final YourLocation locSubs = localLocations.firstWhere(
               (YourLocation localLocation) => localLocation.id == subsLoc.id,