Why: The first S4 pass makes the project the navigation context, keeps deep views in one overlay, and leaves domain panels empty until a plugin declares them.
Evidence: npx tsc -b and npm test (61 passed) in modules/frontend.
Impact: Top bar, project sidebar, inbox all/todo filter, one-way scroll sync, drag-and-drop on the whole chat column, and local molv/system themes.
Refs: feature/s4-shell-overhaul
Co-authored-by: Cursor <cursoragent@cursor.com>
