fix(ui): unify extension update check and improve update affordance

- Update availability is now decided solely by the backend live GitHub
  check (updateFlags); the store index may lag and previously masked
  new versions in the market view.
- Replace the ambiguous refresh icon on extension cards with a labeled
  update button, and add a red dot badge on extension icons (card and
  detail view) when an update is available.
- Surface a toast when the update check fails instead of failing silently.

ui/flutter/lib/features/extensions/application/extensions_controller.dart

@@ -49,6 +49,7 @@ class ExtensionsState {
     this.loadingMoreStore = false,
     this.busyExtensionIds = const {},
     this.devMode = false,
+    this.updateCheckFailed = false,
   });
 
   final List<Extension> installedExtensions;
@@ -63,6 +64,7 @@ class ExtensionsState {
   final bool loadingMoreStore;
   final Set<String> busyExtensionIds;
   final bool devMode;
+  final bool updateCheckFailed;
 
   UnmodifiableMapView<String, Extension> get installedMap =>
       UnmodifiableMapView({for (final ext in installedExtensions) ext.identity: ext});
@@ -100,6 +102,7 @@ class ExtensionsState {
     bool? loadingMoreStore,
     Set<String>? busyExtensionIds,
     bool? devMode,
+    bool? updateCheckFailed,
   }) {
     return ExtensionsState(
       installedExtensions: installedExtensions ?? this.installedExtensions,
@@ -114,6 +117,7 @@ class ExtensionsState {
       loadingMoreStore: loadingMoreStore ?? this.loadingMoreStore,
       busyExtensionIds: busyExtensionIds ?? this.busyExtensionIds,
       devMode: devMode ?? this.devMode,
+      updateCheckFailed: updateCheckFailed ?? this.updateCheckFailed,
     );
   }
 }
@@ -185,12 +189,11 @@ class ExtensionsController extends AsyncNotifier<ExtensionsState> {
   }
 
   bool canUpdateItem(ExtensionListItem item) {
-    final current = _current;
-    if (item.installed == null) return false;
-    if (current.listFilter == ExtensionListFilter.market && item.store != null) {
-      return _compareVersion(item.store!.version, item.installed!.version) > 0;
-    }
-    return current.updateFlags.containsKey(item.installed!.identity);
+    final installed = item.installed;
+    if (installed == null) return false;
+    // The backend checks GitHub live for every installed extension; the store
+    // index may lag behind and must not decide update visibility.
+    return _current.updateFlags.containsKey(installed.identity);
   }
 
   Future<void> installFromStore(StoreExtension extension) async {
@@ -257,15 +260,23 @@ class ExtensionsController extends AsyncNotifier<ExtensionsState> {
 
   Future<void> checkUpdate() async {
     final flags = <String, String>{};
+    var failed = false;
     for (final ext in _current.installedExtensions) {
       try {
         final resp = await ref.read(gopeedServiceProvider).upgradeCheckExtension(ext.identity);
         if (resp.newVersion.isNotEmpty) {
           flags[ext.identity] = resp.newVersion;
         }
-      } catch (_) {}
+      } catch (_) {
+        failed = true;
+      }
     }
-    state = AsyncValue.data(_current.copyWith(updateFlags: flags));
+    state = AsyncValue.data(
+      _current.copyWith(
+        updateFlags: flags,
+        updateCheckFailed: failed && _current.installedExtensions.isNotEmpty,
+      ),
+    );
   }
 
   void tryOpenDevMode() {
@@ -354,24 +365,4 @@ class ExtensionsController extends AsyncNotifier<ExtensionsState> {
     }());
   }
 
-  static int _compareVersion(String a, String b) {
-    final aNums = _toVersionNumbers(a);
-    final bNums = _toVersionNumbers(b);
-    final maxLen = aNums.length > bNums.length ? aNums.length : bNums.length;
-    for (var i = 0; i < maxLen; i++) {
-      final left = i < aNums.length ? aNums[i] : 0;
-      final right = i < bNums.length ? bNums[i] : 0;
-      if (left > right) return 1;
-      if (left < right) return -1;
-    }
-    return 0;
-  }
-
-  static List<int> _toVersionNumbers(String version) {
-    return version
-        .split(RegExp(r'[^0-9]+'))
-        .where((part) => part.isNotEmpty)
-        .map((part) => int.tryParse(part) ?? 0)
-        .toList();
-  }
 }

ui/flutter/lib/features/extensions/presentation/pages/extensions_page.dart

@@ -106,6 +106,12 @@ class _ExtensionsPageState extends ConsumerState<ExtensionsPage> {
       });
     }
     final stateAsync = ref.watch(extensionsControllerProvider);
+    ref.listen(extensionsControllerProvider, (previous, next) {
+      final failed = next.value?.updateCheckFailed ?? false;
+      if (failed && previous?.value?.updateCheckFailed != true) {
+        showAppToast(context, context.l10n.extensionUpdateCheckFailed);
+      }
+    });
     final body = Stack(
       children: [
         ColoredBox(
@@ -485,25 +491,7 @@ class _Content extends StatelessWidget {
   }
 
   bool _canUpdate(ExtensionsState state, ExtensionListItem item) {
-    if (item.installed == null) return false;
-    if (state.listFilter == ExtensionListFilter.market && item.store != null) {
-      return _compareVersion(item.store!.version, item.installed!.version) > 0;
-    }
-    return state.updateFlags.containsKey(item.installed!.identity);
-  }
-
-  int _compareVersion(String a, String b) {
-    final aNums = a.split(RegExp(r'[^0-9]+')).where((part) => part.isNotEmpty).map((part) => int.tryParse(part) ?? 0);
-    final bNums = b.split(RegExp(r'[^0-9]+')).where((part) => part.isNotEmpty).map((part) => int.tryParse(part) ?? 0);
-    final left = aNums.toList();
-    final right = bNums.toList();
-    final maxLen = left.length > right.length ? left.length : right.length;
-    for (var i = 0; i < maxLen; i++) {
-      final l = i < left.length ? left[i] : 0;
-      final r = i < right.length ? right[i] : 0;
-      if (l != r) return l.compareTo(r);
-    }
-    return 0;
+    return item.installed != null && state.updateFlags.containsKey(item.installed!.identity);
   }
 }
 
@@ -988,7 +976,27 @@ class _ExtensionCard extends ConsumerWidget {
         children: [
           Row(
             children: [
-              ExtensionIcon(item: item, size: 40, borderRadius: BorderRadius.circular(6), fallbackFit: BoxFit.cover),
+              Stack(
+                clipBehavior: Clip.none,
+                children: [
+                  ExtensionIcon(item: item, size: 40, borderRadius: BorderRadius.circular(6), fallbackFit: BoxFit.cover),
+                  if (canUpdate)
+                    Positioned(
+                      top: -3,
+                      right: -3,
+                      child: Container(
+                        key: ValueKey('extension-card-update-dot-${item.id}'),
+                        width: 11,
+                        height: 11,
+                        decoration: BoxDecoration(
+                          color: palette.error,
+                          shape: BoxShape.circle,
+                          border: Border.all(color: palette.cardBg, width: 2),
+                        ),
+                      ),
+                    ),
+                ],
+              ),
               const SizedBox(width: 10),
               Expanded(
                 child: Column(
@@ -1068,11 +1076,11 @@ class _ExtensionCard extends ConsumerWidget {
                 mainAxisSize: MainAxisSize.min,
                 children: [
                   if (canUpdate && installed != null)
-                    shad.GhostButton(
-                      density: shad.ButtonDensity.icon,
+                    shad.PrimaryButton(
                       key: ValueKey('update-extension-${installed.identity}'),
+                      density: shad.ButtonDensity.dense,
                       onPressed: busy ? null : () => showExtensionUpdateDialog(context, installed),
-                      child: const Icon(Icons.refresh),
+                      child: Text(context.l10n.extensionUpdateAction),
                     ),
                   if (installed == null && item.store != null)
                     shad.GhostButton(

ui/flutter/lib/features/extensions/presentation/widgets/extension_detail_view.dart

@@ -65,12 +65,32 @@ class ExtensionDetailView extends ConsumerWidget {
           key: const ValueKey('extension-details-hero'),
           crossAxisAlignment: CrossAxisAlignment.start,
           children: [
-            ExtensionIcon(
-              item: current,
-              size: mobile ? 60 : 68,
-              borderRadius: BorderRadius.circular(14),
-              fallbackPadding: EdgeInsets.all((mobile ? 60 : 68) * 0.16),
-              fallbackBackgroundColor: palette.surfaceSoft,
+            Stack(
+              clipBehavior: Clip.none,
+              children: [
+                ExtensionIcon(
+                  item: current,
+                  size: mobile ? 60 : 68,
+                  borderRadius: BorderRadius.circular(14),
+                  fallbackPadding: EdgeInsets.all((mobile ? 60 : 68) * 0.16),
+                  fallbackBackgroundColor: palette.surfaceSoft,
+                ),
+                if (canUpdate)
+                  Positioned(
+                    top: -2,
+                    right: -2,
+                    child: Container(
+                      key: const ValueKey('extension-details-update-dot'),
+                      width: 13,
+                      height: 13,
+                      decoration: BoxDecoration(
+                        color: palette.error,
+                        shape: BoxShape.circle,
+                        border: Border.all(color: palette.bg, width: 2.5),
+                      ),
+                    ),
+                  ),
+              ],
             ),
             SizedBox(width: mobile ? 16 : 20),
             Expanded(
@@ -135,7 +155,7 @@ class ExtensionDetailView extends ConsumerWidget {
                 key: const ValueKey('extension-details-update'),
                 loading: false,
                 variant: AppLoadingButtonVariant.primary,
-                icon: const Icon(Icons.refresh, size: 16),
+                icon: const Icon(Icons.upgrade, size: 16),
                 onPressed: busy ? null : () => showExtensionUpdateDialog(context, installed),
                 child: Text(context.l10n.newVersionUpdate),
               ),

ui/flutter/lib/l10n/app_en.arb

@@ -120,6 +120,8 @@
     }
   },
   "extensionUpdateSuccess": "Updated successfully",
+  "extensionUpdateAction": "Update",
+  "extensionUpdateCheckFailed": "Failed to check for updates. Please check your network",
   "extensionDelete": "Delete Extension",
   "extensionAlreadyLatest": "It's already the latest version",
   "extensionFind": "Find Extensions",

ui/flutter/lib/l10n/app_zh.arb

@@ -106,6 +106,8 @@
   "extensionInstallSuccess": "安装成功",
   "extensionUpdateConfirm": "确定将“{name}”更新到最新版本吗？",
   "extensionUpdateSuccess": "更新成功",
+  "extensionUpdateAction": "更新",
+  "extensionUpdateCheckFailed": "检查更新失败，请检查网络后重试",
   "extensionDelete": "删除扩展",
   "extensionAlreadyLatest": "已经是最新版本",
   "extensionFind": "获取扩展",