Implemented namespace/project/plan/skill permission model with role
bindings (owner/admin/editor/viewer) and default deny policy. Added
enforcement hooks at CLI/service boundaries that are server-only; local
mode returns permissive defaults. Includes role enums, permission check
service, role matrix documentation.
Includes Behave BDD scenarios, Robot integration tests, ASV benchmarks,
and reference documentation.
ISSUES CLOSED: #344