feat(12.1-01): declared record actions with an applicability rule

- pact.HasAdminRecordActions with AdminRecordAction (Applies, Run)
- config_form.yaml recordActions, compiled fail-loud
- show response meta.actions lists the permitted actions that apply
- POST .../{controller}/{id}/actions/{action}: record loaded and locked
  through the form scope; 404 out of scope, 409 when it does not apply
- RecordActions.vue with confirm and request flow (mounted by plan 02)
- roster fixture, smoke tests, OpenAPI, TS types, READMEs, docs

docs/backend/forms.md

@@ -27,6 +27,8 @@ update:
 
 `modelClass` must equal the controller's `pact.AdminController.ModelName`. The `~/plugins/<vendor>/<plugin>/` prefix points into the plugin's own embedded tree.
 
+An optional `recordActions` key lists the record actions the form offers, by the names the controller registers through `pact.HasAdminRecordActions`. The show response of a record then carries `meta.actions`: the declared actions the administrator may run and that apply to the record in its current state. See [Record actions](admin-controllers.md#record-actions).
+
 ## fields.yaml
 
 ```yaml src=modules/cabana/testdata/docs/models/post/fields.yaml