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

update-manifest.json

@@ -1,10 +1,10 @@
 {
-  "versionCode": 100110,
-  "versionName": "10.1.10",
-  "minSupportedVersionCode": 0,
+  "versionCode": 100111,
+  "versionName": "10.1.11",
+  "minSupportedVersionCode": 100000,
   "forceUpdate": false,
-  "downloadUrl": "http://gitea.cbcren.online/renato97/app/releases/download/v10.1.10/StreamPlayer-v10.1.10-debug.apk",
-  "fileName": "StreamPlayer-v10.1.10-debug.apk",
-  "sizeBytes": 9113609,
-  "notes": "Cambiar a HTTP para evitar errores de certificado"
+  "downloadUrl": "",
+  "fileName": "",
+  "sizeBytes": 0,
+  "notes": "StreamPlayer VPN Edition - Configura tu propia URL de actualizaciones en build.gradle"
 }