feat: add PWA support with offline capabilities

- Add web app manifest with icons and theme configuration
- Add service worker with cache-first strategy for static assets
- Add useServiceWorker hook for SW registration
- Add PWA meta tags and Apple-specific tags to index.html
- Update vite.config.ts for optimal asset caching

public/manifest.json

@@ -0,0 +1,40 @@
+{
+  "name": "Termix",
+  "short_name": "Termix",
+  "description": "A web-based server management platform with SSH terminal, tunneling, and file editing capabilities",
+  "theme_color": "#09090b",
+  "background_color": "#09090b",
+  "display": "standalone",
+  "orientation": "any",
+  "scope": "/",
+  "start_url": "/",
+  "icons": [
+    {
+      "src": "/icons/48x48.png",
+      "sizes": "48x48",
+      "type": "image/png"
+    },
+    {
+      "src": "/icons/64x64.png",
+      "sizes": "64x64",
+      "type": "image/png"
+    },
+    {
+      "src": "/icons/128x128.png",
+      "sizes": "128x128",
+      "type": "image/png"
+    },
+    {
+      "src": "/icons/256x256.png",
+      "sizes": "256x256",
+      "type": "image/png"
+    },
+    {
+      "src": "/icons/512x512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any maskable"
+    }
+  ],
+  "categories": ["utilities", "developer", "productivity"]
+}