feat: make Personal Workspace installable as a PWA

public/sw.js

@@ -0,0 +1,47 @@
+// Only this generic page is cached. Authenticated HTML, API responses, and
+// mutations always use the network. Bump the version when offline.html changes.
+const CACHE = "workspace-offline-v1";
+const OFFLINE_URL = "/offline.html";
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(
+    caches.open(CACHE).then((cache) => cache.add(new Request(OFFLINE_URL, { cache: "reload" }))),
+  );
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    (async () => {
+      const keys = await caches.keys();
+      await Promise.all(
+        keys
+          .filter((key) => key.startsWith("workspace-offline-") && key !== CACHE)
+          .map((key) => caches.delete(key)),
+      );
+      await self.clients.claim();
+    })(),
+  );
+});
+
+self.addEventListener("fetch", (event) => {
+  const { request } = event;
+  const url = new URL(request.url);
+  if (
+    request.method !== "GET" ||
+    request.mode !== "navigate" ||
+    url.origin !== self.location.origin ||
+    url.pathname.startsWith("/api/") ||
+    url.pathname.startsWith("/_serverFn/") ||
+    url.pathname.startsWith("/oauth/") ||
+    url.pathname === "/mcp" ||
+    url.pathname === "/health"
+  ) {
+    return;
+  }
+  event.respondWith(
+    fetch(request).catch(async () => {
+      const cache = await caches.open(CACHE);
+      return (await cache.match(OFFLINE_URL)) ?? Response.error();
+    }),
+  );
+});