fix(ui): card chip spacing, instant flag clearing, locale-wide label

- Space the update chip off the card title to match the detail header
- Clear the extension's update flag right after a successful upgrade so
  the chip disappears without waiting for the background re-check
- Use the concise Update label across all locales

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

@@ -243,6 +243,9 @@ class ExtensionsController extends AsyncNotifier<ExtensionsState> {
     await _runBusy(extension.identity, () async {
       await ref.read(gopeedServiceProvider).updateExtension(extension.identity);
       await loadInstalled(refreshUpdates: false);
+      // Drop the stale flag immediately; the background re-check confirms it.
+      final flags = Map<String, String>.of(_current.updateFlags)..remove(extension.identity);
+      state = AsyncValue.data(_current.copyWith(updateFlags: flags));
       unawaited(checkUpdate());
       _bumpStoreInstallCount(extension.identity);
       _reportInstallSafe(extension.identity);

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

@@ -993,7 +993,8 @@ class _ExtensionCard extends ConsumerWidget {
                             style: TextStyle(color: palette.textPrimary, fontSize: 14, fontWeight: FontWeight.w700),
                           ),
                         ),
-                        if (canUpdate && installed != null)
+                        if (canUpdate && installed != null) ...[
+                          const SizedBox(width: 8),
                           Flexible(
                             child: ExtensionUpdateStatus(
                               key: ValueKey('extension-card-update-status-${item.id}'),
@@ -1001,6 +1002,7 @@ class _ExtensionCard extends ConsumerWidget {
                               onTap: busy ? null : () => showExtensionUpdateDialog(context, installed),
                             ),
                           ),
+                        ],
                       ],
                     ),
                     const SizedBox(height: 2),