chore: v0.6.0 baseline — 主题美化前存档

已实现：HTTP/TCP/Banner 探测、90 天可用率、表格/卡片视图、
数据源过滤、UptimeRobot 双向兼容、服务端驱动的刷新节奏、
刷新接口滥用防护与信息泄露控制。

public/index.html

@@ -0,0 +1,49 @@
+<!doctype html>
+<html lang="zh-CN">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <meta name="description" content="轻量级服务监控面板：HTTP 可用性与 TCP 端口探测">
+  <title>Shiroko Monitor</title>
+  <link rel="icon" type="image/svg+xml" href="assets/favicon.svg">
+  <link rel="stylesheet" href="assets/style.css">
+</head>
+<body>
+  <header class="topbar">
+    <div class="brand">
+      <span class="logo" aria-hidden="true"></span>
+      <div class="brand-text">
+        <h1 id="site-title">Shiroko Monitor</h1>
+        <p id="site-desc">轻量级服务监控面板</p>
+      </div>
+    </div>
+    <div class="summary">
+      <span id="overall-pill" class="pill pending">检测中…</span>
+      <div class="stat"><b id="stat-total">–</b><label>监控数</label></div>
+      <div class="stat stat-up"><b id="stat-up">–</b><label>在线</label></div>
+      <div class="stat stat-down"><b id="stat-down">–</b><label>离线</label></div>
+      <div class="stat"><b id="stat-latency">–</b><label>平均延迟</label></div>
+      <div class="stat"><b id="stat-uptime">–</b><label>90天可用率</label></div>
+      <div class="view-switch" id="view-switch" role="group" aria-label="视图切换"></div>
+      <button id="refresh-btn" type="button">刷新</button>
+    </div>
+  </header>
+
+  <nav class="group-tabs" id="group-tabs" aria-label="分组筛选"></nav>
+
+  <main class="grid" id="monitor-grid">
+    <div class="empty">正在加载监控配置…</div>
+  </main>
+
+  <footer class="footer">
+    <span id="source-badge" class="footer-item">数据源：–</span>
+    <span id="demo-chip" class="footer-item demo-chip" hidden>演示数据</span>
+    <span id="ur-chip" class="footer-item warn-chip" hidden>UptimeRobot 同步异常</span>
+    <span id="updated-at" class="footer-item">–</span>
+    <span id="countdown" class="footer-item">–</span>
+    <span class="footer-item version">shiroko-monitor v0.6.0</span>
+  </footer>
+
+  <script type="module" src="assets/app.js"></script>
+</body>
+</html>