feat(mobile): Skia wave, wave player view, themes and playback settings (M5)

- My Wave is rendered with react-native-skia on the UI thread; physics
  and colour helpers moved to @pipu/core (wave-anim) and shared with web.
- Full-screen player honours ui_prefs.mobile_player (cover / wave).
- Theme switching (dark / light / system) via a theme context and
  useColors() across all screens.
- Profile: theme, wave variant, player view, sound quality sheet
  (Wi-Fi / mobile / downloads), recent-tracks cache clearing on next
  cold start, and a change-password sheet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/mobile/package.json

@@ -16,6 +16,7 @@
     "@pipu/design-tokens": "workspace:*",
     "@pipu/i18n": "workspace:*",
     "@react-native-community/netinfo": "11.4.1",
+    "@shopify/react-native-skia": "2.0.0-next.4",
     "@tanstack/react-query": "^5.104.4",
     "expo": "~53.0.20",
     "expo-build-properties": "~0.14.8",
@@ -34,6 +35,7 @@
     "react": "19.0.0",
     "react-i18next": "^15.5.3",
     "react-native": "0.79.6",
+    "react-native-reanimated": "~3.17.5",
     "react-native-safe-area-context": "5.4.0",
     "react-native-screens": "~4.11.1",
     "react-native-track-player": "^4.1.2"