web：service worker 不再拦截导航（修 Safari OAuth 回跳 ~2min 卡顿）

SW 之前以 network-first 接管所有导航请求，疑似在 Safari 下令 Casdoor→应用的回跳导航长时间挂起（~2min 似卡在 Casdoor 页）。改为：导航、/api、跨源一律直通网络，SW 只对同源 hash 化静态资源做 stale-while-revalidate。cdrop 离线无意义，放弃导航壳缓存无损失。cache 版本 bump v2 清旧缓存。

web/public/sw.js

@@ -1,32 +1,24 @@
-// cdrop service worker — makes the web app installable and caches the static
-// shell for instant launch.
+// cdrop service worker — makes the web app installable and caches hashed static
+// assets for faster repeat loads.
 //
-// HARD RULE: it MUST NOT intercept /api/* . The SSE stream (/api/hub/events),
-// clipboard, WebRTC signaling and relay all need a live, unbuffered network
-// connection — those requests are passed straight through to the network. Same
-// goes for cross-origin requests (fonts / CDN): the browser handles them.
+// Deliberately minimal. It does NOT intercept:
+//   - /api/*        — SSE (/api/hub/events), clipboard, signaling, relay need a
+//                     live, unbuffered connection; and the OAuth exchange/refresh
+//                     must not be cached.
+//   - navigations   — page loads / OAuth redirects go straight to the network.
+//                     (A SW that mediates navigations was stalling the Casdoor →
+//                     app redirect for ~2 min in Safari; cdrop is useless offline
+//                     anyway, so there's nothing to gain by caching the shell.)
+//   - cross-origin  — fonts / CDN are left to the browser.
 //
-// cdrop is useless offline (everything needs the backend), so this is a shell
-// cache for fast loads + installability, not a real offline app.
+// What's left: hashed JS/CSS/image assets, served stale-while-revalidate.
 
-const CACHE = "cdrop-shell-v1";
-const SHELL = [
-    "/",
-    "/site.webmanifest",
-    "/favicon-96.png",
-    "/icon-192.png",
-    "/apple-touch-icon-180.png",
-    "/logo-mark.png",
-];
+const CACHE = "cdrop-assets-v2";
 
 self.addEventListener("install", (event) =>
 {
-    event.waitUntil(
-        caches.open(CACHE)
-            .then((cache) => cache.addAll(SHELL))
-            .then(() => self.skipWaiting())
-            .catch(() => self.skipWaiting()),
-    );
+    // No precache — assets are cached lazily on first fetch. Activate immediately.
+    event.waitUntil(self.skipWaiting());
 });
 
 self.addEventListener("activate", (event) =>
@@ -42,29 +34,14 @@ self.addEventListener("fetch", (event) =>
 {
     const req = event.request;
     if (req.method !== "GET") { return; }
+    if (req.mode === "navigate") { return; }                 // page loads / OAuth redirects → network
 
     const url = new URL(req.url);
-    if (url.origin !== self.location.origin) { return; }   // cross-origin (fonts/CDN) → browser default
-    if (url.pathname.startsWith("/api/")) { return; }       // live backend → never intercept
+    if (url.origin !== self.location.origin) { return; }      // cross-origin (fonts/CDN) → browser default
+    if (url.pathname.startsWith("/api/")) { return; }         // live backend → never intercept
 
-    // SPA navigations: network-first so a new deploy serves fresh HTML (which
-    // points at the new hashed assets); fall back to the cached shell offline.
-    if (req.mode === "navigate")
-    {
-        event.respondWith(
-            fetch(req)
-                .then((resp) =>
-                {
-                    const copy = resp.clone();
-                    caches.open(CACHE).then((c) => c.put("/", copy)).catch(() => {});
-                    return resp;
-                })
-                .catch(() => caches.match("/").then((r) => r || Response.error())),
-        );
-        return;
-    }
-
-    // Static assets (hashed JS/CSS/images are immutable): stale-while-revalidate.
+    // Static assets (Vite emits content-hashed, immutable files): serve cache
+    // immediately, refresh in the background.
     event.respondWith(
         caches.match(req).then((cached) =>
         {