feat: add Goldfish Recap YouTube summary PWA

YouTube subtitles via OpenRouter become persistent, shareable recaps
with timestamp jump links, PIN-protected creation, and Traefik deploy.

Co-authored-by: Cursor <cursoragent@cursor.com>

public/sw.js

@@ -0,0 +1,34 @@
+const CACHE = "goldfish-v1";
+const ASSETS = ["/", "/index.html", "/r.html", "/styles.css", "/app.js", "/recap.js", "/api.js", "/manifest.json", "/icon.svg"];
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(caches.open(CACHE).then((cache) => cache.addAll(ASSETS)));
+  self.skipWaiting();
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k)))
+    )
+  );
+  self.clients.claim();
+});
+
+self.addEventListener("fetch", (event) => {
+  const url = new URL(event.request.url);
+  if (url.pathname.startsWith("/api/")) return;
+
+  event.respondWith(
+    caches.match(event.request).then((cached) => {
+      if (cached) return cached;
+      return fetch(event.request).then((resp) => {
+        if (resp.ok && event.request.method === "GET" && url.origin === self.location.origin) {
+          const clone = resp.clone();
+          caches.open(CACHE).then((cache) => cache.put(event.request, clone));
+        }
+        return resp;
+      });
+    })
+  );
+});