Create Schedule screen (part 1)

[zsmb13]

Adds the initial implementation for the schedule screen. First PR of multiple, so that we don't need to review all of this in a single go.

Includes:

• A ViewModel for the sessions screen, offloading the list calculation operations to background threads
• Displaying the list of sessions
• Session feedback handling
• The top Day buttons skipping to the appropriate days (and updating based on scroll state)
• Filtering for bookmarked only
• Entering search mode, filtering for names and session titles, with handling of diacritics
• In search mode, filtering by tags

TODOs remaining (also in the code):

• The "Now" button for the header
• Displaying when a session is coming up soon or currently live
• Highlighting workshops in a separate scroller at the top
• Service events
• Filtering tags being based on real data instead of hardcoded values
• Some improvements on date and string handling (currently too hardcoded)
• State preservation around navigation

Screen.Recording.2025-02-02.at.22.39.36.mov

[kropp]

I added some minor comments, and there are a bunch of TODOs in the code, but given that it is just the first part of a bigger PR, I assume it is okay.