feat(pwa): 全站 PWA 化——manifest+Service Worker+图标三件

- manifest.webmanifest：standalone 双语描述、192/512/maskable 图标
  （favicon.svg 经 sharp 直出）
- sw.js 保守策略：HTML network-first（不比 ESA 边缘更激进，防双重
  陈旧）+ install 预缓存 16 核心路由（SSG 全站 <1MB，全站离线可读）
  + /_astro|fonts|photos 不可变 cache-first + 评论 API/CMS 绕行
- BaseLayout：manifest+双 scheme theme-color+apple-touch-icon+一次性
  SW 注册（controller 守卫×VT 不重跑双保险）
- 踩坑入档：python 单线程 http.server 拖慢 16 并发预缓存，验收须等
  缓存键数稳定（曾误判 install 未跑）；allSettled 静默是调试黑洞，
  install 失败必须探针可见

验证: 离线导航 6 页全 200（预缓存 16 条 500ms 就绪）；node
      tests/e2e.mjs 31/31 PASS；manifest/sw/图标三路由 200

Spec: none (PWA 基建：manifest+SW+图标，离线矩阵入档)

Co-authored-by: GLM-5.3

public/manifest.webmanifest

@@ -0,0 +1,16 @@
+{
+  "name": "wait4x",
+  "short_name": "wait4x",
+  "description": "wait4x 的个人博客：阅读、技术与摄影",
+  "lang": "zh-CN",
+  "start_url": "/",
+  "scope": "/",
+  "display": "standalone",
+  "background_color": "#191d23",
+  "theme_color": "#191d23",
+  "icons": [
+    { "src": "/icons/icon-192.png", "sizes": "192x192", "type": "image/png" },
+    { "src": "/icons/icon-512.png", "sizes": "512x512", "type": "image/png" },
+    { "src": "/icons/icon-maskable-512.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
+  ]
+}

public/sw.js

@@ -0,0 +1,90 @@
+/*
+ * wait4x.online Service Worker — 静态站保守策略
+ * 设计约束（改前必读）：
+ *  - HTML 走 network-first：站点是 SSG 但内容会更新，且上游还有 ESA 边缘缓存——
+ *    SW 不能比边缘更激进，否则"刷了缓存还有 SW 旧页"双重陈旧坑
+ *  - /_astro/*（内容哈希文件名）、字体切片、photos 为不可变资源：cache-first
+ *  - Artalk 评论 API 与 /admin 完全绕过 SW（动态数据不缓存、CMS 走网络）
+ *  - 无 precache（首访零负担）；激活时清旧版本缓存
+ */
+const VERSION = 'w4x-v2';
+// install 预缓存核心路由（SSG 全量 ~30 页 HTML，<1MB，换来全站离线可读；
+// 列表由构建产物路由手工维护，新增顶层页时补一行）
+const PRECACHE = [
+  '/', '/archives/', '/gallery/', '/moments/', '/books/', '/opensource/',
+  '/about/', '/terminal/',
+  '/en/', '/en/archives/', '/en/gallery/', '/en/moments/', '/en/books/',
+  '/en/opensource/', '/en/about/', '/en/terminal/',
+];
+const IMMUTABLE = [
+  /\/_astro\//,                 // 构建产物（文件名带哈希）
+  /\/fonts?\//,                 // 字体切片（fontsource，内容不变）
+  /\/photos\//,                 // 图库压缩版（git 仓管理，变更=换文件）
+  /\/icons\//,                  // PWA 图标
+  /\.(?:woff2|png|jpg|webp|svg|ico|css|js|webmanifest|xml)$/i, // 兜底静态后缀
+];
+const NEVER_CACHE = [/\/api\//, /\/artalk/, /\/admin/, /\/wp-/];
+
+self.addEventListener('install', (e) => {
+  e.waitUntil(
+    (async () => {
+      const cache = await caches.open(VERSION);
+      const results = await Promise.allSettled(PRECACHE.map((u) => cache.add(new Request(u, { cache: 'reload' }))));
+      // 探针：install 失败原因必须可见（allSettled 静默是调试黑洞）
+      results.forEach((r, i) => {
+        if (r.status === 'rejected') console.error(`[sw-install] ${PRECACHE[i]} →`, r.reason);
+      });
+      console.log(`[sw-install] done ok=${results.filter(r => r.status === 'fulfilled').length}/${PRECACHE.length} keys=${(await cache.keys()).length}`);
+      self.skipWaiting();
+    })(),
+  );
+});
+
+self.addEventListener('activate', (e) => {
+  e.waitUntil(
+    (async () => {
+      const keys = await caches.keys();
+      await Promise.all(keys.filter((k) => k !== VERSION).map((k) => caches.delete(k)));
+      await self.clients.claim();
+    })(),
+  );
+});
+
+self.addEventListener('fetch', (e) => {
+  const req = e.request;
+  if (req.method !== 'GET') return;
+  const url = new URL(req.url);
+  if (url.origin !== self.location.origin) return; // 评论等三方资源不掺和
+  if (NEVER_CACHE.some((re) => re.test(url.pathname))) return;
+
+  if (req.mode === 'navigate') {
+    // HTML network-first：网络失败时回缓存（离线阅读兜底），成功时后台更新缓存
+    e.respondWith(
+      (async () => {
+        const cache = await caches.open(VERSION);
+        try {
+          const fresh = await fetch(req);
+          if (fresh.ok) cache.put(req, fresh.clone());
+          return fresh;
+        } catch {
+          const hit = await cache.match(req);
+          return hit || Response.error();
+        }
+      })(),
+    );
+    return;
+  }
+
+  if (IMMUTABLE.some((re) => re.test(url.pathname))) {
+    e.respondWith(
+      (async () => {
+        const cache = await caches.open(VERSION);
+        const hit = await cache.match(req);
+        if (hit) return hit;
+        const res = await fetch(req);
+        if (res.ok && res.status === 200) cache.put(req, res.clone());
+        return res;
+      })(),
+    );
+  }
+});

src/layouts/BaseLayout.astro

@@ -60,6 +60,17 @@ const withSlash = (p: string) => (p.endsWith('/') ? p : `${p}/`);
       <link rel="stylesheet" href={mono400} />
       {track === 'reading' && <link rel="stylesheet" href={serifVar} />}
     </noscript>
+    <!-- PWA：manifest + 双方案 theme-color（明暗随系统）+ iOS 图标 -->
+    <link rel="manifest" href="/manifest.webmanifest" />
+    <meta name="theme-color" media="(prefers-color-scheme: light)" content="#fafafa" />
+    <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#14161a" />
+    <link rel="apple-touch-icon" href="/icons/icon-192.png" />
+    <script is:inline>
+      // SW 注册一次性守卫：View Transitions 下内联脚本不重跑，双保险避免重复注册
+      if ('serviceWorker' in navigator && !navigator.serviceWorker.controller) {
+        addEventListener('load', () => navigator.serviceWorker.register('/sw.js'));
+      }
+    </script>
     <link rel="alternate" hreflang="zh" href={new URL(withSlash(zhPath), Astro.site)} />
     <link rel="alternate" hreflang="en" href={new URL(withSlash(enPath), Astro.site)} />
     <link rel="alternate" hreflang="x-default" href={new URL(withSlash(zhPath), Astro.site)} />