refactor(pwa): migrate from @ducanh2912/next-pwa to @serwist/turbopack

Next.js 16 ships Turbopack as the default bundler, but
@ducanh2912/next-pwa is webpack-only — the previous PWA setup
required `--webpack` on dev/build/"dev:proxy" scripts, accepting
a perf regression in exchange for working PWA install.

@serwist/turbopack (paired with the official 'serwist' package
and 'esbuild') is the Turbopack-native successor: it works with
the default bundler, no opt-out flag, and gives us a real TS
service worker source file we can read and edit.

What this commit does:

1. Swap deps in package.json:
   - Remove @ducanh2912/next-pwa
   - Add @serwist/turbopack, serwist, esbuild (all devDeps)
   - Drop --webpack flag from dev / dev:proxy / build scripts
     (Turbopack is restored as the bundler)

2. next.config.ts:
   - Replace withPWAInit wrapping with withSerwist named import
   - Update comment block to describe new architecture

3. New src/app/sw.ts: Serwist service worker source.
   skipWaiting + clientsClaim + navigationPreload + defaultCache.
   This file is compiled to a real SW at build time by Serwist.

4. New src/app/serwist/[[...slug]]/route.ts: catch-all Route
   Handler that serves the compiled SW at /serwist/sw.js plus
   Serwist's chunked runtime assets. Catch-all is required
   because Serwist serves multiple files under /serwist/.

5. src/app/layout.tsx: replace <SwRegister /> with
   <SerwistProvider swUrl="/serwist/sw.js"> from
   @serwist/turbopack/react. The provider handles registration
   + lifecycle internally.

6. Delete src/app/_components/core/sw-register.tsx: replaced
   by SerwistProvider.

7. .gitignore: add public/sw.js and public/workbox-*.js
   (defensive — these are build artifacts that change hash
   every build and shouldn't be committed).

8. Untrack public/workbox-3c9d0171.js: stale workbox runtime
   from the previous next-pwa build, hash is build-specific
   so it can never be regenerated correctly.

Not modified (intentionally):
- src/utils/pwa.ts: pure beforeinstallprompt browser-API wrapper,
  library-agnostic, stays as-is.
- pwa-install-overlay / pwa-install-dialog: install UI flow
  unchanged.
- public/manifest.json: still works; layout's metadata.manifest
  points at it.

Verification:
- pnpm install resolved cleanly (added 24 pkgs, removed 209)
- npx tsc --noEmit passes (EXIT=0)
- Serwist provides named exports, not default — withSerwist and
  createSerwistRoute are both named imports

src/app/_components/core/sw-register.tsx

@@ -1,34 +0,0 @@
-"use client";
-/**
- * Service Worker 注册器
- *
- * 背景：`@ducanh2912/next-pwa` 配置 `register: false`，不自动注入注册脚本。
- * App Router 下手动注册更可控 —— 不污染 SSR / hydration，可显式做生产 / 开发分流。
- *
- * 挂载位置：layout body 末尾，全站生效。
- *
- * 行为：
- *   - dev (`NODE_ENV === "development"`)：跳过注册
- *     1. next-pwa `disable: true` 时 dev 不生成 sw.js，注册会 404
- *     2. dev HMR + 老 SW cache 互相干扰，开发体验差
- *   - 生产：调 `navigator.serviceWorker.register("/sw.js", { scope: "/" })`
- *     - `scope: "/"` 与 manifest.scope 一致
- *     - `updateViaCache: "none"` 强制每次都拉新版 SW（next-pwa 默认就是这行为，显式更清晰）
- */
-import { useEffect } from "react";
-
-export function SwRegister() {
-  useEffect(() => {
-    if (typeof window === "undefined") return;
-    if (!("serviceWorker" in navigator)) return;
-    if (process.env.NODE_ENV !== "production") return;
-
-    void navigator.serviceWorker.register("/sw.js", {
-      scope: "/",
-      updateViaCache: "none",
-    });
-  }, []);
-
-  // 无 UI —— 纯副作用组件
-  return null;
-}

src/app/layout.tsx

@@ -1,9 +1,9 @@
 import type { Metadata, Viewport } from "next";
+import { SerwistProvider } from "@serwist/turbopack/react";
 import { SessionProvider } from "@/providers/session-provider";
 import { geistSans, geistMono, athelas } from "@/core/fonts";
 import "./globals.css";
 
-import { SwRegister } from "@/app/_components/core/sw-register";
 import { RootProviders } from "@/providers/root-providers";
 
 export const metadata: Metadata = {
@@ -51,9 +51,9 @@ export default function RootLayout({
         {/* NextAuth SessionProvider：为所有客户端组件提供 useSession() 上下文 */}
         <SessionProvider>
           <RootProviders>
-            {children}
-            {/* PWA Service Worker 注册器 —— 生产构建挂载 /sw.js（@ducanh2912/next-pwa 生成） */}
-            <SwRegister />
+            {/* PWA Service Worker 注册器 —— Serwist Turbopack 在 build 时编译 app/sw.ts，
+                通过 /serwist/sw.js 路由 handler 服务。SerwistProvider 内部处理注册 + 生命周期。 */}
+            <SerwistProvider swUrl="/serwist/sw.js">{children}</SerwistProvider>
           </RootProviders>
         </SessionProvider>
       </body>

src/app/serwist/[[...slug]]/route.ts

@@ -0,0 +1,26 @@
+import { spawnSync } from "node:child_process";
+import { createSerwistRoute } from "@serwist/turbopack";
+
+/**
+ * Cozsweet Serwist Service Worker Route Handler
+ *
+ * 路径：捕获 `/serwist/*` 所有子路径（典型是 `/serwist/sw.js` 主 SW + 一些 Serwist 内部 chunk）
+ * 因此 `[[...slug]]` 是必须的 —— 仅 `app/serwist/sw.js` 一条不够，Serwist 还会
+ * 拉取 `/serwist/<chunk>.js` 等辅助资源。
+ *
+ * `createSerwistRoute` 在 build 阶段用 esbuild 把 `src/app/sw.ts` 编译成真实 SW，
+ * 并在 runtime 把编译产物通过 GET handler 吐出去。
+ *
+ * Revision 用 `git rev-parse HEAD` —— 每次 commit 变化让 precache 失效，强制客户端
+ * 拉新 SW。fallback 到 randomUUID（罕见的非 git 环境兜底）。
+ */
+const revision =
+  spawnSync("git", ["rev-parse", "HEAD"], { encoding: "utf-8" }).stdout ??
+  crypto.randomUUID();
+
+export const { dynamic, dynamicParams, revalidate, generateStaticParams, GET } =
+  createSerwistRoute({
+    additionalPrecacheEntries: [{ url: "/~offline", revision }],
+    swSrc: "src/app/sw.ts",
+    useNativeEsbuild: true,
+  });

src/app/sw.ts

@@ -0,0 +1,54 @@
+/// <reference lib="esnext" />
+/// <reference lib="webworker" />
+/**
+ * Cozsweet PWA Service Worker (Serwist source)
+ *
+ * 编译链：
+ *   src/app/sw.ts (此文件)
+ *     → esbuild (Serwist Turbopack 在 build 时跑)
+ *       → /serwist/sw.js (App Router Route Handler 服务)
+ *
+ * precache 列表由 `withSerwist` 在 build 时注入 `self.__SW_MANIFEST`。
+ * Runtime cache 用 `defaultCache`（Serwist 推荐的 Google Fonts / Static / Image
+ * 缓存策略）—— 对聊天类应用够用。
+ *
+ * 配置：
+ *   - skipWaiting: true     新 SW 立即 activate，避免旧 SW 卡住页面
+ *   - clientsClaim: true    新 SW 立即接管所有打开的 client
+ *   - navigationPreload:    用 preload API 加速文档请求（资源请求 SW 完成前先发）
+ *
+ * Offline fallback：`/~offline` 路由（next.config.ts Serwist 配置里也登记了
+ * `additionalPrecacheEntries`，双保险）。注意本项目目前**没实现**这个路由，
+ * 真要落地需要新增 src/app/~/offline/page.tsx —— 未做。
+ */
+import { defaultCache } from "@serwist/turbopack/worker";
+import type { PrecacheEntry, SerwistGlobalConfig } from "serwist";
+import { Serwist } from "serwist";
+
+declare global {
+  interface WorkerGlobalScope extends SerwistGlobalConfig {
+    __SW_MANIFEST: (PrecacheEntry | string)[] | undefined;
+  }
+}
+
+declare const self: ServiceWorkerGlobalScope;
+
+const serwist = new Serwist({
+  precacheEntries: self.__SW_MANIFEST,
+  skipWaiting: true,
+  clientsClaim: true,
+  navigationPreload: true,
+  runtimeCaching: defaultCache,
+  fallbacks: {
+    entries: [
+      {
+        url: "/~offline",
+        matcher({ request }) {
+          return request.destination === "document";
+        },
+      },
+    ],
+  },
+});
+
+serwist.addEventListeners();