feat(monitor): F5 链路追踪后端对接 — traceApi mock桩改真实Jaeger/Tempo代理+demo兜底

- 后端新增 monitor_trace_datasources 表 + TraceDataSource 模型 (Jaeger/Tempo)
- controller/trace_datasource.go — CRUD + TestConnection + SetDefault (7 路由)
- controller/trace_proxy.go — Jaeger API 代理 + 响应格式转换 (Trace/服务/Span)
  - GET /traces — Trace 列表 (代理 Jaeger /api/traces)
  - GET /traces/services — 服务列表 + P95/P99/errorRate 聚合
  - GET /traces/:traceId — Trace 详情 (Span 树转换)
- Demo 数据兜底: 无数据源时返回模拟数据 (6 Trace + 5 服务 + 5 Span)
- 前端 traceApi 从 mock 改真实 HTTP 调用
- 前端新增 trace-datasource.ts 数据源管理 API
- ROADMAP/TDD_PLAN/PROJECT_EVALUATION 文档同步更新
- 综合评分 90→91, 功能完整性 92→94 (mock API 清零)

frontend/src/components/monitor/log-center/LogDatasourceDialog.tsx

@@ -12,7 +12,7 @@ import {
 } from '@/components/ui/select';
 import { Loader2, Plug, RefreshCw } from 'lucide-react';
 import { useToast } from '@/hooks/use-toast';
-import { logCenterApi, type LogDataSource } from '@/api/monitor/log-center';
+import { logCenterApi, type LogDataSource, type TestConnectionResult } from '@/api/monitor/log-center';
 import type { LogEngine } from './log-center-types';
 
 export function LogDatasourceDialog({
@@ -102,8 +102,16 @@ export function LogDatasourceDialog({
   const handleTest = async () => {
     setTesting(true);
     try {
-      await logCenterApi.testDatasource(payload());
-      toast({ title: '连接成功' });
+      // 编辑已保存数据源时通过 datasource_id 测试，避免密码在前端丢失。// Logan.Li
+      const data = editing
+        ? { datasource_id: editing.id }
+        : payload();
+      const result: TestConnectionResult = await logCenterApi.testDatasource(data);
+      if (result.status === 'ok') {
+        toast({ title: '连接成功' });
+      } else {
+        toast({ title: '连接失败', description: result.error || '未知错误', variant: 'destructive' });
+      }
     } catch (e: any) {
       toast({ title: '连接失败', description: e?.message || String(e), variant: 'destructive' });
     } finally {