feat: Add WFW-Aushang web app with PWA support, offline caching, and dark mode

- Created index.html for the main application interface with responsive design and dark mode support.
- Added manifest.webmanifest for PWA configuration, including app icons and display settings.
- Implemented service worker (sw.js) for offline caching of assets and network-first strategy for versioning.
- Introduced version.json to manage app versioning.

zuss/manifest.webmanifest

@@ -0,0 +1,14 @@
+{
+  "name": "WFW-Aushang",
+  "short_name": "WFW-Aushang",
+  "start_url": "/zuss/",
+  "scope": "/zuss/",
+  "display": "fullscreen",
+  "orientation": "portrait",
+  "background_color": "#0b1020",
+  "theme_color": "#0b1020",
+  "icons": [
+    { "src": "/zuss/icons/icon-192.png", "sizes": "192x192", "type": "image/png" },
+    { "src": "/zuss/icons/icon-512.png", "sizes": "512x512", "type": "image/png" }
+  ]
+}