feat(web): show Box runtime status in plugin debug info popover

Add Box status section to the debug info popover on the plugin list page,
displaying connection status, backend info, profile, active sessions,
and recent error count. Fetched from GET /api/v1/box/status in parallel
with plugin debug info. Includes i18n for all 8 supported languages.

web/src/app/infra/http/BackendClient.ts

@@ -35,6 +35,7 @@ import {
   ApiRespProviderRerankModel,
   RerankModel,
   ApiRespPluginSystemStatus,
+  ApiRespBoxStatus,
   ApiRespMCPServers,
   ApiRespMCPServer,
   MCPServer,
@@ -889,6 +890,10 @@ export class BackendClient extends BaseHttpClient {
     return this.get('/api/v1/plugins/debug-info');
   }
 
+  public getBoxStatus(): Promise<ApiRespBoxStatus> {
+    return this.get('/api/v1/box/status');
+  }
+
   // ============ User API ============
   public checkIfInited(): Promise<{ initialized: boolean }> {
     return this.get('/api/v1/user/init');