fix(backend): Resolve PgBoss infinite loop issue and cleanup unused files

Backend fixes:
- Fix PgBoss task infinite loop on SAE (root cause: missing queue table constraints)
- Add singletonKey to prevent duplicate job enqueueing
- Add idempotency check in reviewWorker (skip completed tasks)
- Add optimistic locking in reviewService (atomic status update)

Frontend fixes:
- Add isSubmitting state to prevent duplicate submissions in RVW Dashboard
- Fix API baseURL in knowledgeBaseApi (relative path)

Cleanup (removed):
- Old frontend/ directory (migrated to frontend-v2)
- python-microservice/ (unused, replaced by extraction_service)
- Root package.json and node_modules (accidentally created)
- redcap-docker-dev/ (external dependency)
- Various temporary files and outdated docs in root

New documentation:
- docs/07-运维文档/01-PgBoss队列监控与维护.md
- docs/07-运维文档/02-故障预防检查清单.md
- docs/07-运维文档/03-数据库迁移注意事项.md

Database fix applied to RDS:
- Added PRIMARY KEY to platform_schema.queue
- Added 3 missing foreign key constraints

Tested: Local build passed, RDS constraints verified

frontend-v2/src/modules/rvw/components/AgentModal.tsx

@@ -10,9 +10,10 @@ interface AgentModalProps {
   taskCount: number;
   onClose: () => void;
   onConfirm: (agents: AgentType[]) => void;
+  isSubmitting?: boolean; // 🔒 防止重复提交
 }
 
-export default function AgentModal({ visible, taskCount, onClose, onConfirm }: AgentModalProps) {
+export default function AgentModal({ visible, taskCount, onClose, onConfirm, isSubmitting = false }: AgentModalProps) {
   const [selectedAgents, setSelectedAgents] = useState<AgentType[]>(['editorial']);
 
   const toggleAgent = (agent: AgentType) => {
@@ -110,10 +111,10 @@ export default function AgentModal({ visible, taskCount, onClose, onConfirm }: A
           </button>
           <button 
             onClick={handleConfirm}
-            disabled={selectedAgents.length === 0}
+            disabled={selectedAgents.length === 0 || isSubmitting}
             className="px-4 py-2 bg-indigo-600 hover:bg-indigo-700 text-white text-sm font-bold rounded-lg shadow-sm transition-colors disabled:opacity-50 disabled:cursor-not-allowed"
           >
-            立即运行
+            {isSubmitting ? '提交中...' : '立即运行'}
           </button>
         </div>
       </div>
@@ -140,6 +141,9 @@ export default function AgentModal({ visible, taskCount, onClose, onConfirm }: A
 
 
 
+
+
+