This track addresses the fragmented implementation of Session Context Snapshots
and Discussion Takes & Timeline Branching tracks (2026-03-11) which were
marked complete but the UI panel layout was not properly reorganized.
New track structure:
- Phase 1: Remove ui_summary_only, rename Context Hub to Project Settings
- Phase 2: Merge Session Hub into Discussion Hub (4 tabs)
- Phase 3: Context Composition tab (per-discussion file filter)
- Phase 4: DAW-style Takes timeline integration
- Phase 5: Final integration and cleanup
Also archives the two botched tracks and updates tracks.md.