Fix PWA shortcut icon on Windows

Allow unauthenticated access to favicon and manifest, generate favicon.ico, and add multi-size manifest icons.

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

assets/site/site.webmanifest

@@ -3,20 +3,33 @@
   "short_name": "道德经",
   "description": "传统文化典籍资料库",
   "start_url": "/",
+  "scope": "/",
   "display": "standalone",
   "background_color": "#1a1a2e",
   "theme_color": "#0f3460",
   "icons": [
     {
-      "src": "/apple-touch-icon.png",
-      "sizes": "512x512",
-      "type": "image/png",
-      "purpose": "any maskable"
+      "src": "/favicon.ico",
+      "sizes": "48x48",
+      "type": "image/x-icon"
     },
     {
-      "src": "/favicon.png",
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "any"
+    },
+    {
+      "src": "/icon-512.png",
       "sizes": "512x512",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "maskable"
     }
   ]
 }