Remove dashboard/VPS references - make project PR-ready

- Remove DeviceRegistry.java (dashboard integration)
- Remove VPS IP from build.gradle
- Remove personal Gitea token from UpdateManager
- Add configurable UPDATE_CHECK_URL for updates
- Clean README to be generic and PR-ready
- Clean update manifests
- Remove Docker files and .env from repo

release/update-manifest.example.json

@@ -1,10 +1,10 @@
 {
-  "versionCode": 90000,
-  "versionName": "9.0.0",
-  "minSupportedVersionCode": 80000,
+  "versionCode": 100111,
+  "versionName": "10.1.11",
+  "minSupportedVersionCode": 100000,
   "forceUpdate": false,
-  "downloadUrl": "https://gitea.cbcren.online/renato97/app/releases/download/v9.0/StreamPlayer-v9.0-DefinitiveEdition.apk",
-  "fileName": "StreamPlayer-v9.0-DefinitiveEdition.apk",
-  "sizeBytes": 12000000,
-  "notes": "Texto opcional si necesitas personalizar las notas que verá el usuario"
+  "downloadUrl": "https://your-gitea-instance.com/your-user/your-repo/releases/download/v10.1.11/StreamPlayer-v10.1.11.apk",
+  "fileName": "StreamPlayer-v10.1.11.apk",
+  "sizeBytes": 20000000,
+  "notes": "StreamPlayer VPN Edition\n\nConfigura UPDATE_CHECK_URL en app/build.gradle para habilitar actualizaciones automáticas."
 }