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/models/appState.dart

@@ -19,7 +19,6 @@ part 'appState.g.dart';
 @immutable
 @JsonSerializable(nullable: false)
 class AppState {
-
   const AppState(
       {this.yourLocations = const <YourLocation>[],
       this.fireNotifications = const <FireNotification>[],
@@ -35,10 +34,8 @@ class AppState {
       this.monitoredAreas = const <Polyline>[],
       this.fireMapState = const FireMapState.initial()});
 
-  @JsonKey(ignore: true)
   factory AppState.fromJson(Map<String, dynamic> json) =>
       _$AppStateFromJson(json);
-  @JsonKey(ignore: true)
   final bool isLoading;
   @JsonKey(ignore: true)
   final bool isLoaded;
@@ -102,7 +99,8 @@ class AppState {
 
 typedef AddYourLocationFunction = void Function(YourLocation loc);
 typedef DeleteYourLocationFunction = void Function(YourLocation loc);
-typedef OnRefreshYourLocationsFunction = void Function(Completer<void> callback);
+typedef OnRefreshYourLocationsFunction = void Function(
+    Completer<void> callback);
 typedef ToggleSubscriptionFunction = void Function(YourLocation loc);
 typedef OnLocationTapFunction = void Function(YourLocation loc);
 typedef OnSubscribeFunction = void Function(YourLocation loc);
@@ -114,7 +112,8 @@ typedef OnLocationEditing = void Function(YourLocation loc);
 typedef OnLocationEditConfirm = void Function(YourLocation loc);
 typedef OnLocationEditCancel = void Function(YourLocation loc);
 typedef TapFireNotificationFunction = void Function(FireNotification notif);
-typedef OnFirePressedInMap = void Function(LatLng latLng, DateTime when, String source);
+typedef OnFirePressedInMap = void Function(
+    LatLng latLng, DateTime when, String source);
 // typedef void OnReceivedFireNotificationFunction(FireNotification notif);
 typedef DeleteFireNotificationFunction = void Function(FireNotification notif);
 typedef DeleteAllFireNotificationFunction = void Function();