feat: initial commit - oncology literature search platform

OncoLit: a multi-tenant oncology literature search, feed, and
collaboration platform. Built with FastAPI + Vue 3 + PostgreSQL.
Includes PubMed pipeline, drug approvals, AI summaries, and
systematic review tools.

frontend/public/sw.js

@@ -0,0 +1,28 @@
+// Service Worker — 离线缓存 + 推送通知
+const CACHE_NAME = 'scilit-oncology-v1';
+const STATIC_ASSETS = ['/', '/app/feed', '/app/search', '/app/library'];
+
+self.addEventListener('install', (event) => {
+  (event as any).waitUntil(
+    caches.open(CACHE_NAME).then((cache) => cache.addAll(STATIC_ASSETS))
+  );
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+  (event as any).waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(keys.filter((k) => k !== CACHE_NAME).map((k) => caches.delete(k)))
+    )
+  );
+  self.clients.claim();
+});
+
+self.addEventListener('fetch', (event) => {
+  const req = (event as FetchEvent).request;
+  // API 请求不缓存
+  if (req.url.includes('/api/')) return;
+  (event as any).respondWith(
+    caches.match(req).then((cached) => cached || fetch(req))
+  );
+});