Move "about osm" to about page, add option to clear tile caches, option to add reason when deleting, min zoom 16 for edits/submissions, 300km nav distance warning

lib/state/settings_state.dart

@@ -4,6 +4,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 import 'package:collection/collection.dart';
 
 import '../models/tile_provider.dart';
+import '../services/provider_tile_cache_manager.dart';
 import '../dev_config.dart';
 import '../keys.dart';
 
@@ -332,6 +333,17 @@ class SettingsState extends ChangeNotifier {
     notifyListeners();
   }
 
+  /// Clear all tile caches for a specific provider
+  Future<void> clearTileProviderCaches(String providerId) async {
+    final provider = _tileProviders.firstWhereOrNull((p) => p.id == providerId);
+    if (provider == null) return;
+    
+    // Clear cache for each tile type in this provider
+    for (final tileType in provider.tileTypes) {
+      await ProviderTileCacheManager.deleteCache(providerId, tileType.id);
+    }
+  }
+
   /// Set follow-me mode
   Future<void> setFollowMeMode(FollowMeMode mode) async {
     if (_followMeMode != mode) {