feat: 添加PWA支持，支持离线访问和添加到主屏幕

company-finance-system/frontend/public/sw.js

@@ -0,0 +1,70 @@
+// Service Worker for PWA
+const CACHE_NAME = 'qingyuan-erp-v1';
+const STATIC_ASSETS = [
+  '/',
+  '/index.html',
+  '/manifest.json',
+  '/logo.png'
+];
+
+// 安装时缓存静态资源
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => {
+      return cache.addAll(STATIC_ASSETS);
+    }).catch((err) => {
+      console.log('Cache failed:', err);
+    })
+  );
+  self.skipWaiting();
+});
+
+// 激活时清理旧缓存
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames
+          .filter((name) => name !== CACHE_NAME)
+          .map((name) => caches.delete(name))
+      );
+    })
+  );
+  self.clients.claim();
+});
+
+// 拦截请求，优先使用缓存
+self.addEventListener('fetch', (event) => {
+  // 跳过非GET请求和API请求
+  if (event.request.method !== 'GET' || 
+      event.request.url.includes('/api/') ||
+      event.request.url.includes('chrome-extension')) {
+    return;
+  }
+
+  event.respondWith(
+    caches.match(event.request).then((response) => {
+      // 如果缓存中有，返回缓存
+      if (response) {
+        return response;
+      }
+
+      // 否则发起网络请求
+      return fetch(event.request).then((networkResponse) => {
+        // 缓存新请求
+        if (networkResponse.status === 200) {
+          const responseToCache = networkResponse.clone();
+          caches.open(CACHE_NAME).then((cache) => {
+            cache.put(event.request, responseToCache);
+          });
+        }
+        return networkResponse;
+      }).catch(() => {
+        // 网络失败时返回离线页面
+        if (event.request.mode === 'navigate') {
+          return caches.match('/index.html');
+        }
+      });
+    })
+  );
+});