rebrand app from Bocken Fitness to Bocken, track Android project

- Manifest: name/short_name → "Bocken", start_url → "/"
- Tauri: productName → "Bocken", identifier → org.bocken.app, url → "/"
- Cargo: package → bocken, lib → bocken_lib
- Page titles: "- Fitness" → "- Bocken" across all fitness routes
- Build script: auto-regenerate android project on identifier change
- Regenerate app icon from website favicon
- Track Android project source in git (ignore only build output/caches)
- Add native GPS foreground service and AndroidBridge for background
  location tracking (LocationForegroundService, AndroidBridge.kt)
- Add ACCESS_BACKGROUND_LOCATION permission for screen-off GPS

src-tauri/gen/schemas/capabilities.json

@@ -0,0 +1 @@
+{"bocken-remote":{"identifier":"bocken-remote","description":"","remote":{"urls":["https://bocken.org/*","http://192.168.1.4:5173/*"]},"local":true,"windows":["main"],"permissions":["geolocation:allow-check-permissions","geolocation:allow-request-permissions","geolocation:allow-get-current-position","geolocation:allow-watch-position","geolocation:allow-clear-watch"]}}