improve image lifecycle handling

app/lib/features/geckoview/domain/providers/tab_state.dart

@@ -331,6 +331,11 @@ class TabStates extends _$TabStates {
     );
 
     ref.onDispose(() async {
+      // Dispose all remaining tab images
+      for (final tab in state.values) {
+        _disposeTabImages(tab);
+      }
+
       // Cancel all stream subscriptions
       for (final sub in subscriptions) {
         await sub.cancel();

app/lib/features/geckoview/domain/providers/tab_state.g.dart

@@ -41,7 +41,7 @@ final class TabStatesProvider
   }
 }
 
-String _$tabStatesHash() => r'2d18c0c2105ce53bd13e6a6dff1d33c1b531919d';
+String _$tabStatesHash() => r'985d2eb87c59c3a113b8bbcf9d96267c42a2f543';
 
 abstract class _$TabStates extends $Notifier<Map<String, TabState>> {
   Map<String, TabState> build();

app/lib/features/geckoview/domain/providers/web_extensions_state.dart

@@ -71,8 +71,8 @@ class WebExtensionsState extends _$WebExtensionsState {
     } else {
       if (state.containsKey(extensionId)) {
         state = {...state}..remove(extensionId);
-        // Dispose the cached image when extension is removed
-        _imageCache.remove(extensionId)?.dispose();
+        // remove() triggers onEvict which handles disposal
+        _imageCache.remove(extensionId);
       }
     }
   }
@@ -83,9 +83,7 @@ class WebExtensionsState extends _$WebExtensionsState {
     final image = await tryDecodeImage(bytes);
 
     if (image != null) {
-      // Dispose old image only after successfully creating new one
-      _imageCache.get(extensionId)?.dispose();
-
+      // set() will evict the old entry via onEvict callback, which handles disposal
       _imageCache.set(extensionId, image);
 
       if (state.containsKey(extensionId)) {

app/lib/features/geckoview/domain/providers/web_extensions_state.g.dart

@@ -62,7 +62,7 @@ final class WebExtensionsStateProvider
 }
 
 String _$webExtensionsStateHash() =>
-    r'd74f739a2f33395c10e30a81c8031f2f2630e418';
+    r'28cd9c99bc167fa1a051eccf3d23917a417e54ea';
 
 final class WebExtensionsStateFamily extends $Family
     with