fix: inject app version from package.json instead of hardcoded 1.0.0

- Add Vite define for __APP_VERSION__ from package.json
- Use dynamic version in gateway connect handshake and userAgent
- Show version number in sidebar footer
- Add globals.d.ts type declaration

src/globals.d.ts

@@ -0,0 +1 @@
+declare const __APP_VERSION__: string;