fix: resolve 78 strict analysis errors with explicit type annotations

Implemented systematic type safety improvements across the codebase to eliminate all 78 strict analysis errors:

## Phase 1: Quick Wins (Redux & Model Fixes)
- Added explicit type annotations to Redux reducer parameters
- Fixed copyWith() methods in FireNotification and YourLocation models with proper nullable types
- Fixed BasicLocation field initializers with type casts (num to double)
- Fixed context parameter inference in IntroPage and PrivacyPage
- Regenerated .g.dart files with build_runner

## Phase 2: JSON Deserialization
- Fixed homePage.dart Firebase message parameter casting (9 errors)
- Fixed firesApi.dart JSON parsing:
  - Added explicit casts for num to double/int conversions
  - Fixed array iteration with proper List<dynamic> casting
  - Added return type annotation to objectIdFromJson()
  - Fixed nested JSON access in getMonitoredAreas()
- Fixed globalFiresBottomStats.dart dynamic to int/String casting
- Fixed locationUtils.dart string assignments

## Phase 3: Config & Redux Middleware
- Fixed mainCommon.dart config map access with explicit String casts
- Fixed mainProd.dart Sentry DSN casting
- Fixed fetchDataMiddleware.dart:
  - Added Store<AppState>, String type annotations to createUser()
  - Added Function(YourLocation) type to subscribeViaApi callback
  - Added Exception type to catchError handler
- Fixed fireMapReducer.dart restoreStatusAfterSave parameter type
- Fixed persist files with Map<String, dynamic> type annotations

## Phase 4: Edge Cases
- Fixed slider.dart method return types (Widget sizeText, Widget warningText)
- Fixed mainDrawer.dart Key? parameter type annotation

Result: 78 errors → 0 errors

lib/models/yourLocation.g.dart

@@ -6,21 +6,25 @@ part of 'yourLocation.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-YourLocation _$YourLocationFromJson(Map json) {
-  return $checkedNew('YourLocation', json, () {
-    final val = YourLocation(
-      id: $checkedConvert(json, 'id', (v) => objectIdFromJson(v as String)),
-      lat: $checkedConvert(json, 'lat', (v) => (v as num).toDouble()),
-      lon: $checkedConvert(json, 'lon', (v) => (v as num).toDouble()),
-      description: $checkedConvert(json, 'description', (v) => v as String),
-      distance: $checkedConvert(json, 'distance', (v) => v as int),
-      currentNumFires:
-          $checkedConvert(json, 'currentNumFires', (v) => v as int),
-      subscribed: $checkedConvert(json, 'subscribed', (v) => v as bool),
+YourLocation _$YourLocationFromJson(Map json) => $checkedCreate(
+      'YourLocation',
+      json,
+      ($checkedConvert) {
+        final val = YourLocation(
+          id: $checkedConvert('id', (v) => objectIdFromJson(v as String)),
+          lat: $checkedConvert('lat', (v) => (v as num).toDouble()),
+          lon: $checkedConvert('lon', (v) => (v as num).toDouble()),
+          description:
+              $checkedConvert('description', (v) => v as String? ?? ''),
+          distance:
+              $checkedConvert('distance', (v) => (v as num?)?.toInt() ?? 10),
+          currentNumFires:
+              $checkedConvert('currentNumFires', (v) => (v as num?)?.toInt()),
+          subscribed: $checkedConvert('subscribed', (v) => v as bool? ?? false),
+        );
+        return val;
+      },
     );
-    return val;
-  });
-}
 
 Map<String, dynamic> _$YourLocationToJson(YourLocation instance) =>
     <String, dynamic>{