feat: integrate MarkBase Search Session API into Studio

- Created useSearchSession composable for session management
- Added 7 API endpoints in api/index.ts
- Updated SearchView.vue to use sessions instead of history
- Session sidebar with create, rename, delete functionality
- Auto-save messages to current session after each search
- Auto-create default session on first load
- Updated CSS for session active state and new session button

src/api/index.ts

@@ -685,6 +685,22 @@ case 'search_keyword': {
       return { url: '/api/v2/admin/users', method: 'GET', requiresAdminToken: true }
     case 'list_shares':
       return { url: '/api/v2/admin/shares', method: 'GET' }
+
+    // --- Search Sessions ---
+    case 'list_search_sessions':
+      return { url: '/api/v2/search-sessions', method: 'GET', requiresAdminToken: true }
+    case 'create_search_session':
+      return { url: '/api/v2/search-sessions', method: 'POST', body: { title: a.title, mode: a.mode }, requiresAdminToken: true }
+    case 'rename_search_session':
+      return { url: `/api/v2/search-sessions/${a.id}`, method: 'PUT', body: { title: a.title }, requiresAdminToken: true }
+    case 'delete_search_session':
+      return { url: `/api/v2/search-sessions/${a.id}`, method: 'DELETE', requiresAdminToken: true }
+    case 'get_session_messages':
+      return { url: `/api/v2/search-sessions/${a.sessionId}/messages`, method: 'GET', requiresAdminToken: true }
+    case 'save_session_message':
+      return { url: `/api/v2/search-sessions/${a.sessionId}/messages`, method: 'POST', body: a.message, requiresAdminToken: true }
+    case 'update_session_message':
+      return { url: `/api/v2/search-sessions/${a.sessionId}/messages/${a.msgId}`, method: 'PATCH', body: a.message, requiresAdminToken: true }
     case 'admin_login':
       return { url: '/api/v2/admin/login', method: 'POST', body: { username: a.username, password: a.password } }