macosx: Display internal track titles from cue/m3u files in playqueue

This commit enhances the macOS playqueue UI to properly display track-specific titles from cue sheets and m3u playlists instead of showing generic file names.

Key changes:

• VLCPlayQueueTableCellView: Enhanced title display logic to prioritize inputItem.title over generic item.title when available, with optional track number prefixing (format: "Track# · Title")
• VLCPlayQueueController: Improved playQueueUpdatedForIndex to safely replace items using current playlist state rather than potentially stale callback data, preventing crashes during rapid updates
• VLCPlayQueueModel: Added replaceItemAtIndex:withItem: method for atomic item replacement in the queue array

This allows users to see meaningful track titles like "03 · Song Name" instead of just the cue/m3u filename for each track, significantly improving the user experience when playing cuesheets or structured playlists.

Addresses playlist metadata display issues where individual tracks from cue sheets and m3u files were showing generic filenames rather than their embedded track titles and numbers.