Release-cycle test audit found the role feature's security-critical paths
untested. Adds real unit tests (against the actual functions):
- resolveRoleForRequest invariants: role comes from chat.roleId not body.roleId
(no per-turn swap), lookup scoped to workspace.id, disabled/soft-deleted role
-> null, new-chat uses body.roleId, stale chatId falls back.
- CASL admin gate: non-admin create/update/delete -> Forbidden and service not
called; admin delegates with workspace.id; list() is member-reachable.
- roleModelOverride: unknown driver dropped (never reaches getChatModel's
throwing default), valid override passes through, blanks ignored.
- getChatModel override success path (cross-driver fetch + decrypt; chatModel-
only reuse), and service update/remove cross-workspace 'not found' guards +
modelConfig tri-state.
Tiny fix: findByCreator badge left-join now also requires enabled=true, so a
disabled role (downgraded to universal by resolveRoleForRequest) no longer shows
a misleading chat-list badge.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>