Add the Slice-Zero catalog and selection HTTP surfaces for P3 Task 3:
GET /api/harnesses, GET /api/harnesses/:harnessId/catalog,
GET+PUT /api/chat/preferences/selection. Scope is always server-derived
via scopeFromUser(CurrentUser); selection tuples are validated against the
live catalog with no fallback substitution and persisted in a transitional
owner-scoped in-memory store. HarnessModule is wired into AppModule.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01ESFAnh2t9HmLwng8oW95St