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/fireAlert.dart

@@ -29,8 +29,11 @@ class _FireAlertState extends State<FireAlert> {
       child: FloatingActionButton(
         heroTag: 'callAction',
         child: const Icon(Icons.call),
-        onPressed: () {
-          launch('tel://112');
+        onPressed: () async {
+          final Uri url = Uri(scheme: 'tel', path: '112');
+          if (await canLaunchUrl(url)) {
+            await launchUrl(url);
+          }
         },
       ),
     );
@@ -58,20 +61,16 @@ class _FireAlertState extends State<FireAlert> {
         heroTag: 'tweetAction',
         child: const Icon(CommunityMaterialIcons.twitter),
         onPressed: () {
-          // In Android you can choose with app to use with setPackage but seems it's not implemented here
-          // https://stackoverflow.com/questions/6814268/android-share-on-facebook-twitter-mail-ecc
           openPlacesDialog(_scaffoldKey).then((YourLocation yourLocation) {
             final String where =
                 yourLocation.description.replaceAll(' ', '').split(',')[0];
-            print(where);
             Share.shareWithResult(S
                 .of(context)
                 .tweetAboutSelf(yourLocation.description, '#IF$where'));
-          }).catchError((onError) {
-            final BuildContext? ctx = _scaffoldKey.currentContext;
-            if (ctx != null) {
-              ScaffoldMessenger.of(ctx).showSnackBar(SnackBar(
-                  content: Text(S.of(ctx).errorFirePlaceDialog)));
+          }).catchError((Object onError) {
+            if (mounted) {
+              ScaffoldMessenger.of(context).showSnackBar(
+                  SnackBar(content: Text(S.of(context).errorFirePlaceDialog)));
             }
           });
         },