Backend already defined automations:create/read/update/delete/execute and
seeded them on Owner/Editor/Viewer roles, but the Settings → Roles UI was
missing the metadata to render them properly.
- backend: add PERMISSION_DESCRIPTIONS entries for the 5 automations perms so
the role editor stops falling back to "Permission for automations:create".
- frontend: add automations to CATEGORY_CONFIG (Workflow icon, slotted between
podcasts and connectors) so the role editor groups them as a real section.
- frontend: extend the three ROLE_PRESETS — Editor and Contributor get
create/read/update/execute (mirroring backend Editor); Viewer gets read.
Prep work for the automations frontend; canPerform/usePermissionGate already
handle the runtime gating, so no new hook is needed.
