* feat(rbac): make Settings authorization permission-aware
Align Settings visibility and mutations with the existing permission matrix so Node Admin can edit node-scoped operational settings while system and credential surfaces stay Admin-protected.
* fix(rbac): tighten settings permission buckets and tests
Collapse settings key permission maps into one source of truth, and cover mixed PATCH atomicity plus image-update enabled writes.
* fix(rbac): tighten Settings scoped grants and CI assertions
Empty settings PATCH fails closed, node:manage is scoped to the active
node, system-only Settings stay hidden without system:settings, and
Check updates / webhooks mutate gates follow the permission matrix.
* fix(rbac): defer Settings section fallback until authz is ready
Keep deep links to permission-gated sections (e.g. license) intact while
can() is still fail-closed during permission metadata load.
* docs(settings): clarify Notifications channels vs routing authz
Channels use node:manage via /api/agents; routing and mute stay Admin-only.
Anso