feat: 将 demo 项目转化为 HTTP 拨测监控工具

新增 YAML 配置解析（Bun 内置 YAML）、SQLite 数据存储（bun:sqlite）、按 interval 分组并发拨测引擎、REST API（/api/summary、/api/targets、/api/targets/:id/history、/api/targets/:id/trend）、React 前端 Dashboard（统计卡片、目标表格、可展开详情面板、recharts 趋势图）。CLI 简化为仅接受配置文件路径。移除 /api/demo 路由和相关 demo 代码。保留 /health、静态资源服务和 SPA fallback。

src/web/components/TargetRow.tsx

@@ -0,0 +1,34 @@
+import type { TargetStatus } from "../../shared/api";
+import { StatusDot } from "./StatusDot";
+import { SparklineChart } from "./SparklineChart";
+
+interface TargetRowProps {
+  target: TargetStatus;
+  expanded: boolean;
+  onToggle: () => void;
+}
+
+export function TargetRow({ target, expanded, onToggle }: TargetRowProps) {
+  const isUp = target.latestCheck?.success && target.latestCheck?.matched;
+
+  const sparklineData = target.sparkline.map((latency) => ({ latency }));
+
+  return (
+    <tr className={`target-row ${expanded ? "expanded" : ""}`} onClick={onToggle}>
+      <td className="col-status">
+        <StatusDot up={!!isUp} />
+      </td>
+      <td className="col-name">{target.name}</td>
+      <td className="col-url">{target.url}</td>
+      <td className="col-method">{target.method}</td>
+      <td className="col-latency">
+        {target.latestCheck?.latencyMs !== null && target.latestCheck?.latencyMs !== undefined
+          ? `${Math.round(target.latestCheck.latencyMs)}ms`
+          : "-"}
+      </td>
+      <td className="col-sparkline">
+        <SparklineChart data={sparklineData} />
+      </td>
+    </tr>
+  );
+}