iOS / iPadOS / tvOS 18 compatibility

[defagos]

As a developer I need Pillarbox to be compatible with new major versions of Apple operating systems.

Hints

Here is a list of the issues we noticed and of work that needs to be done.

Fixes on our side

• ✅ Version plugin: Deprecation errors if package version set to 6.0.

Upgrade work

• Update pbxproj to use folders instead of groups (https://iosdev.space/@kern/113012885194302061). Can only be done after Xcode 16 release.
• Update CI to build with Xcode 16 (ready on a #988).

Xcode 16 / iOS 18 / iPadOS 18 bugs or regressions

• DocC warnings (some symbols not found, working correctly with Xcode 15).
• High-speed gesture not working: System gesture gate timed out is logged to the console.
• 🤔 Settings picker is incorrectly displayed as toolbarTitleMenu at the root level of the Lists section (iPadOS 18: New tab bar presentation and inline navigation title / toolbar title menus do not work well together filed under FB14924375).
• ✅ Startup time incorrect after seeking (✅ local / ✅ AirPlay)
• Playback fails very fast if buffer gets empty (e.g. start playback and enable airplane mode immediately)
• Podcastator: Speed / Timer menus do not open anymore when player displayed as a sheet.

Acceptance criteria

• Pillarbox is compatible with iOS / iPadOS / tvOS 18.
• Issues which cannot be fixed on our side have been reported.
• The project builds with Xcode 16.

Tasks

• [x] ~Update Xcode project to synced folders.~
• [ ] Fix high-speed gesture.
• [ ] Fix settings combo.
• [ ] Fix speed / timer menus in Podcastator.
• [ ] Document unresolved issues under known issues if appropriate.
• [ ] Fix compilation warnings.