…iguration

- **Library**:
    - Implement comprehensive `Paging` load state handling in `LibrarySongsTab`, adding a dedicated error UI with retry functionality and refined skeleton loading logic.
- **Full Player**:
    - Improve progress bar smoothness by driving the slider thumb from smoothed progress and adjusting sampling rates based on expansion state.
    - Update default `FullPlayerLoadingTweaks` to enable placeholders and set the content appear threshold to 98% by default.
    - Refine placeholder logic in `DelayedContent` to ensure they only toggle during motion and stay open when fully expanded.
    - Adjust layout dimensions for controls and bottom toggle rows for better visual spacing.
    - Fix artist navigation to use the first valid artist ID from the song's metadata.
- **Navigation**:
    - Optimize `PlayerInternalNavigationBar` by memoizing click listeners and using `rememberUpdatedState` to prevent unnecessary recompositions.
- **Build & Performance**:
    - Enable R8 Full Mode in `gradle.properties`.
    - Update `proguard-rules.pro` to keep data and domain model members, ensuring compatibility with R8 full mode.