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/UnifiedQueryPanel.tsx

@@ -141,14 +141,16 @@ export function UnifiedQueryPanel({ engine, onRuleCreated }: Props) {
   // 从后端加载真实数据源（无 demo 兜底，无源时引导用户前往日志库配置）// Logan.Li
   const [sources, setSources] = useState<LogDataSource[]>([]);
   useEffect(() => {
-    logCenterApi.listDatasources(effEngine).then((res: any) => {
-      const list: LogDataSource[] = Array.isArray(res) ? res : (res?.list || []);
+    logCenterApi.listDatasources(effEngine).then((res) => {
+      const list: LogDataSource[] = res?.list || [];
       setSources(list);
     }).catch(() => setSources([]));
   }, [effEngine]);
 
   const [query, setQuery] = useState(DEFAULT_QUERIES[effEngine]);
   const [dsId, setDsId] = useState(String(sources[0]?.id || ''));
+  // API 单次查询返回条数上限（后端限制 500），Loki 用 limit / ES 用 size // Logan.Li
+  const [queryLimit, setQueryLimit] = useState(200);
   const [timeRange, setTimeRange] = useState<TimeRange>(DEFAULT_TIME_RANGE);
   const [loading, setLoading] = useState(false);
   const [entries, setEntries] = useState<LogEntry[]>([]);
@@ -204,7 +206,7 @@ export function UnifiedQueryPanel({ engine, onRuleCreated }: Props) {
         result = await logCenterApi.queryLoki({
           datasource_id: dsIdNum,
           query,
-          limit: 200,
+          limit: queryLimit,
           start: startISO,
           end: endISO,
           direction: 'backward',
@@ -213,7 +215,7 @@ export function UnifiedQueryPanel({ engine, onRuleCreated }: Props) {
         result = await logCenterApi.queryElasticsearch({
           datasource_id: dsIdNum,
           query,
-          size: 200,
+          size: queryLimit,
           start: startISO,
           end: endISO,
         });
@@ -246,7 +248,7 @@ export function UnifiedQueryPanel({ engine, onRuleCreated }: Props) {
     } finally {
       setLoading(false);
     }
-  }, [effEngine, query, currentSource, timeRange, toast]);
+  }, [effEngine, query, currentSource, timeRange, toast, queryLimit]);
 
   const toggleField = useCallback((n: string) => setSelectedFields(p => p.includes(n) ? p.filter(f => f !== n) : [...p, n]), []);
   const handleSaveMenu = (a: 'query' | 'alert') => { setSaveMenuOpen(false); a === 'query' ? setSaveQueryOpen(true) : setSaveAlertOpen(true); };
@@ -278,6 +280,22 @@ export function UnifiedQueryPanel({ engine, onRuleCreated }: Props) {
           {sources.map(s => <option key={s.id} value={s.id}>{s.name}{s.is_default ? ' (默认)' : ''}</option>)}
         </select>
 
+        <div className="flex items-center gap-1.5 h-10 px-2 rounded flex-shrink-0" style={{ background: 'var(--dg-bg-tertiary)', border: '1px solid var(--dg-border)' }}>
+          <span className="text-xs text-[var(--dg-text-muted)]">上限</span>
+          <input
+            type="number"
+            min={1}
+            max={500}
+            value={queryLimit}
+            onChange={e => {
+              const v = parseInt(e.target.value, 10);
+              setQueryLimit(Number.isNaN(v) ? 200 : Math.min(500, Math.max(1, v)));
+            }}
+            className="w-14 h-6 text-xs text-center rounded outline-none"
+            style={{ background: 'var(--dg-bg-secondary)', color: 'var(--dg-text-primary)', border: '1px solid var(--dg-border)' }}
+          />
+        </div>
+
         <button onClick={handleRun} disabled={loading || !currentSource} className="h-10 px-4 rounded text-xs font-medium text-white flex items-center gap-1.5 flex-shrink-0 transition-opacity hover:opacity-90" style={{ background: '#22c55e' }}>
           {loading ? <Loader2 className="h-4 w-4 animate-spin" /> : <Play className="h-4 w-4" />} 查询
         </button>