feat(alert): A2 告警引擎分布式安全 — Redis 分布式锁(SetNX)

- Cache 接口新增 SetNX 方法(go-redis 原子 / redka check-then-set 单副本安全)
- AlertEngine 改造为支持分布式锁: tryAcquireLock/releaseLock/GetEngineStatus
- 多副本部署时仅 Leader 执行告警检查, 60s TTL 防死锁, fail-open 容错
- 新增 GET /alerts/engine/status 监控端点(is_leader/instance_id/lock_holder)
- 修复 GrafanaDashboard.tsx Panel.options 类型不匹配导致构建中断
- 同步未提交的前端类型安全迁移(140+ 文件)
- ROADMAP/TDD_PLAN/PROJECT_EVALUATION 三文档同步更新

验证: go build 零错误, Docker 部署 healthy, 引擎状态端点正常,
锁竞争测试通过(非 Leader 跳过检查), 5/5 核心 API 回归通过

frontend/src/components/monitor/dashboard/GrafanaDashboard.tsx

@@ -93,7 +93,7 @@ const AgentTab: React.FC = () => {
     finally { setBatchUninstalling(false); }
   };
   const totalPages = Math.max(1, Math.ceil(hosts.length / pageSize));
-  const fetch = async () => { try { setHosts(asList(await agentApi.getLatest())); } catch {} finally { setLoading(false); } };
+  const fetch = async () => { try { setHosts(asList(await agentApi.getLatest()) as typeof hosts); } catch {} finally { setLoading(false); } };
   useEffect(() => { fetch(); const t = setInterval(fetch, 30000); return () => clearInterval(t); }, []);
   const toggle = (f: SortField) => { if (sf === f) setSd(d => d === 'asc' ? 'desc' : 'asc'); else { setSf(f); setSd('desc'); } };
   const sorted = [...hosts].sort((a, b) => {
@@ -419,7 +419,7 @@ const PrometheusTab: React.FC = () => {
 
 // ═══════════ 自定义仪表盘 ═══════════
 interface Dashboard { id: string; name: string; description: string; datasource: string; datasourceUrl: string; panels: Panel[]; createdAt: string; updatedAt: string; createdBy: string; isDefault: boolean; }
-export interface Panel { id: string; title: string; type: string; query: string; datasource: string; width: number; height: number; x: number; y: number; options: any; }
+export interface Panel { id: string; title: string; type: string; query: string; datasource: string; width: number; height: number; x: number; y: number; options?: any; }
 
 const DashboardTab: React.FC = () => {
   const [dashboards, setDashboards] = useState<Dashboard[]>([]);