conductor(tracks): Add discussion_hub_panel_reorganization track

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.

conductor/tracks.md

@@ -1,4 +1,4 @@
-# Project Tracks
+# Project Tracks
 
 This file tracks all major tracks for the project. Each track has its own detailed plan in its respective folder.
 
@@ -67,14 +67,18 @@ This file tracks all major tracks for the project. Each track has its own detail
    *Link: [./tracks/presets_ai_settings_ux_20260311/](./tracks/presets_ai_settings_ux_20260311/)*
    *Goal: Improve the layout, scaling, and control ergonomics of the Preset windows (Personas, Prompts, Tools) and AI Settings panel. Includes dual-control sliders and categorized tool management.*
 
-8. [x] **Track: Session Context Snapshots & Visibility**
+8. [x] ~~**Track: Session Context Snapshots & Visibility**~~ (Archived 2026-03-22 - Replaced by discussion_hub_panel_reorganization)
    *Link: [./tracks/session_context_snapshots_20260311/](./tracks/session_context_snapshots_20260311/)*
    *Goal: Session-scoped context management, saving Context Presets, MMA assignment, and agent-focused session filtering in the UI.*
 
-9. [x] **Track: Discussion Takes & Timeline Branching**
+9. [x] ~~**Track: Discussion Takes & Timeline Branching**~~ (Archived 2026-03-22 - Replaced by discussion_hub_panel_reorganization)
    *Link: [./tracks/discussion_takes_branching_20260311/](./tracks/discussion_takes_branching_20260311/)*
    *Goal: Non-linear discussion timelines via tabbed "takes", message branching, and synthesis generation workflows.*
 
+12. [ ] **Track: Discussion Hub Panel Reorganization**
+    *Link: [./tracks/discussion_hub_panel_reorganization_20260322/](./tracks/discussion_hub_panel_reorganization_20260322/)*
+    *Goal: Properly merge Session Hub into Discussion Hub (4 tabs: Discussion | Context Composition | Snapshot | Takes), establish Files & Media as project-level inventory, deprecate ui_summary_only, implement Context Composition and DAW-style Takes.*
+
 10. [ ] **Track: Undo/Redo History Support**
     *Link: [./tracks/undo_redo_history_20260311/](./tracks/undo_redo_history_20260311/)*
     *Goal: Robust, non-provider based undo/redo for text inputs, UI controls, discussion mutations, and context management. Includes hotkey support and a history list view.*