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

app.json

@@ -36,7 +36,8 @@
       "favicon": "./assets/favicon.png"
     },
     "plugins": [
-      "expo-router"
+      "expo-router",
+      "react-native-video"
     ],
     "experiments": {
       "typedRoutes": true