Why: T4 acceptance requires a verification record in this repo before the Dev combo pin.
Evidence: backend full sweep green with TestWorkspacesOverlay; ui 23/23 (OverlayHost semantics); frontend tsc+vitest+build; example plugin workspace/command assets JSON-validated; combo make test at pinned heads.
Impact: docs/records only.
Refs: docs/proposals/2026-09-30-ui-inbox-command-workspace.md T4; task card feature/workspaces-r1