feat: redesign Dashboard layout with search and recently used tools

- Add search input at top to filter tools by name/description
- Add 'recently used' section showing last 3 used tools as compact chips
- Add 'all tools' section header for the tool card grid
- Track tool usage via new 'app/recentlyUsedTools' storage key
- Update navigateTo to record recently used tools (max 3, LRU order)
- Add i18n keys: dashboard_searchPlaceholder, dashboard_recentlyUsed, dashboard_allTools

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/types/storage.d.ts

@@ -113,6 +113,8 @@ export interface StorageSchema {
   'app/language': string;
   /** 右键菜单待处理数据 */
   'contextMenu/pendingData': ContextMenuPendingData;
+  /** 最近使用的工具列表（最多保留 3 个） */
+  'app/recentlyUsedTools': PageType[];
 }
 
 /**