feat: unlock 1080P+ on Android via DASH streaming

- getPlayUrl uses fnval=16 (DASH) on Android, keeping fnval=0/html5 for iOS/web
- New utils/dash.ts builds a valid DASH MPD from Bilibili's segmentBase ranges
  and returns it as a data: URI for ExoPlayer consumption
- NativeVideoPlayer selects DASH path (type='mpd') or durl fallback automatically
- Extend PlayUrlResponse types with DashVideoItem/DashAudioItem/DashSegmentBase

package.json

@@ -25,6 +25,7 @@
     "react-native": "0.83.2",
     "react-native-safe-area-context": "~5.6.2",
     "react-native-screens": "~4.23.0",
+    "react-native-video": "^6.19.0",
     "react-native-web": "^0.21.0",
     "react-native-webview": "13.16.0",
     "zustand": "^5.0.11"