feat(ui): implement edge-to-edge support and improve splash transition

- Enable edge-to-edge display in `MainActivity` and handle window insets in `PlayerFragment`.
- Add a fade-out animation when hiding the loading overlay.
- Sync player state with the controller during setup and reset playing state in preferences on service destruction.
- Simplify splash screen drawable and update background color attributes in layout.
- Remove manual navigation bar color overrides.

app/src/main/res/drawable/splash_screen.xml

@@ -4,9 +4,6 @@
     <item
         android:width="160dp"
         android:height="160dp"
-        android:gravity="center">
-        <bitmap
-            android:gravity="center"
-            android:src="@mipmap/ic_launcher" />
-    </item>
+        android:gravity="center"
+        android:drawable="@mipmap/ic_launcher" />
 </layer-list>