feat: 第五轮开发 - 14项未来路线图功能完整实现

W1-W14 全部完成:
- W1: 消息搜索 (ILIKE全文检索 + SearchModal)
- W2: 对话导出 (JSON/Markdown/TXT三格式)
- W3: 记忆时间线 DevTools 可视化
- W4: 通知推送系统 (WebSocket + Browser Notification API)
- W5: 定时提醒 (30s轮询 + 重复提醒 + WebSocket推送)
- W6: 每日简报 (08:00自动生成: 天气+新闻+提醒+AI摘要)
- W7: IoT场景自动化 (规则引擎 10s轮询 + 条件评估 + 场景执行)
- W8: 语音输入 (浏览器 Speech Recognition API)
- W9: STT服务 (voice-service + whisper.cpp)
- W10: TTS服务 (浏览器 Speech Synthesis + edge-tts三档回退)
- W11: 文件管理 (上传/下载/缩略图/纯Go bilinear缩放)
- W12: 知识库RAG (PostgreSQL tsvector + 文档分块 + 检索)
- W13: 多模态 (图片上传+分析: Vision API + 本地Go分析回退)
- W14: PWA (Service Worker + 离线页 + install prompt)

总计: 6个Go微服务 + 10+前端组件 + 10+ PostgreSQL表 + 4个后台调度器

frontend/web/public/sw.js

@@ -0,0 +1,107 @@
+const CACHE_NAME = 'cyrene-v1';
+const ASSETS_TO_CACHE = [
+  '/',
+  '/index.html',
+];
+
+// Install: 缓存核心资源
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => {
+      return cache.addAll(ASSETS_TO_CACHE);
+    })
+  );
+  self.skipWaiting();
+});
+
+// Activate: 清理旧缓存
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((keys) => {
+      return Promise.all(
+        keys.filter(key => key !== CACHE_NAME).map(key => caches.delete(key))
+      );
+    })
+  );
+  self.clients.claim();
+});
+
+// Fetch: 缓存优先策略（对 API 请求使用网络优先）
+self.addEventListener('fetch', (event) => {
+  const url = new URL(event.request.url);
+
+  // API 请求：网络优先，失败时返回离线 JSON
+  if (url.pathname.startsWith('/api/')) {
+    event.respondWith(networkFirst(event.request));
+  } else if (url.pathname.startsWith('/ws')) {
+    // WebSocket 连接不缓存
+    event.respondWith(fetch(event.request));
+  } else {
+    // 静态资源：缓存优先
+    event.respondWith(cacheFirst(event.request));
+  }
+});
+
+async function cacheFirst(request) {
+  const cached = await caches.match(request);
+  if (cached) return cached;
+  try {
+    const response = await fetch(request);
+    if (response.ok) {
+      const cache = await caches.open(CACHE_NAME);
+      cache.put(request, response.clone());
+    }
+    return response;
+  } catch (e) {
+    // 返回离线页面（HTML 请求）
+    if (request.headers.get('Accept')?.includes('text/html')) {
+      return caches.match('/offline.html');
+    }
+    throw e;
+  }
+}
+
+async function networkFirst(request) {
+  try {
+    const response = await fetch(request);
+    const cache = await caches.open(CACHE_NAME);
+    cache.put(request, response.clone());
+    return response;
+  } catch (e) {
+    const cached = await caches.match(request);
+    if (cached) return cached;
+    return new Response(JSON.stringify({ error: '离线状态，请检查网络连接' }), {
+      status: 503,
+      headers: { 'Content-Type': 'application/json' }
+    });
+  }
+}
+
+// Push 通知
+self.addEventListener('push', (event) => {
+  const data = event.data?.json() || { title: 'Cyrene', body: '新消息' };
+  event.waitUntil(
+    self.registration.showNotification(data.title, {
+      body: data.body,
+      icon: '/images/Cyrene_Avatar/2nd_Form/Cyrene-2F-N-Happy-1.png',
+      badge: '/images/Cyrene_Avatar/2nd_Form/Cyrene-2F-N-Happy-1.png',
+      data: data.data || {},
+    })
+  );
+});
+
+self.addEventListener('notificationclick', (event) => {
+  event.notification.close();
+  const sessionId = event.notification.data?.session_id;
+  const targetUrl = sessionId ? `/#/session/${sessionId}` : '/';
+  event.waitUntil(
+    clients.matchAll({ type: 'window' }).then((clientList) => {
+      for (const client of clientList) {
+        if (client.url.includes(targetUrl) && 'focus' in client) {
+          return client.focus();
+        }
+      }
+      if (clients.openWindow) return clients.openWindow(targetUrl);
+    })
+  );
+});