feat: Add PWA support with manifest and ServiceWorker integration

- Mounted static files directory to serve PWA assets like manifest.json and ServiceWorker scripts.
- Updated `auth.html` and `keys_status.html` templates:
  - Added `<link>` for manifest and icons to support Progressive Web App (PWA) features.
  - Added meta tags for theme color and Apple web app capabilities.
  - Integrated ServiceWorker registration script for offline capabilities.

app/main.py

@@ -2,6 +2,7 @@ from fastapi import FastAPI, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import HTMLResponse, RedirectResponse
 from fastapi.templating import Jinja2Templates
+from fastapi.staticfiles import StaticFiles
 from app.core.logger import get_main_logger
 from app.core.security import verify_auth_token
 from app.services.key_manager import get_key_manager_instance
@@ -19,6 +20,9 @@ app = FastAPI()
 # 配置Jinja2模板
 templates = Jinja2Templates(directory="app/templates")
 
+# 配置静态文件
+app.mount("/static", StaticFiles(directory="app/static"), name="static")
+
 # 创建 KeyManager 实例
 key_manager = None