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

modules/pact/capabilities.go

@@ -299,6 +299,50 @@ type HasAdminBulkActions interface {
 	AdminBulkActions() []AdminBulkAction
 }
 
+// AdminRecordAction is one controller action an administrator runs on a
+// single record (config_form.yaml recordActions). The admin framework owns the
+// HTTP route, the CSRF check, authentication, the record lookup and the
+// transaction; Run only carries the business logic and reads the write
+// transaction with cabana.TxFromContext. Name is an identifier unique among
+// the controller's record actions; create and delete are reserved, and a bulk
+// action may use the same name. Label and Confirm are phrase keys or literal
+// text; an empty Confirm means the framework's default confirm text.
+// Permissions are checked in addition to the controller's
+// RequiredPermissions. Applies reports whether the action applies to the
+// record in its current state: a nil Applies means the action always applies.
+// Applies must be a pure read, because it also runs when a record is shown, to
+// decide which actions the admin is offered.
+type AdminRecordAction struct {
+	Name        string
+	Label       string
+	Confirm     string
+	Permissions []string
+	Applies     func(ctx context.Context, record any) (bool, error)                                   `json:"-"`
+	Run         func(ctx context.Context, in AdminRecordActionInput) (AdminRecordActionResult, error) `json:"-"`
+}
+
+// AdminRecordActionInput is what the framework hands an AdminRecordAction.
+// Record is the record the framework loaded through the controller's
+// FormExtendQuery scope with a row lock, inside the action's transaction;
+// RecordID is its primary key.
+type AdminRecordActionInput struct {
+	RecordID uint64
+	Record   any
+}
+
+// AdminRecordActionResult is a record action's answer. Message is a phrase key
+// or text, localized by the framework and shown as a toast; when it is empty
+// the admin shows its default text.
+type AdminRecordActionResult struct {
+	Message string
+}
+
+// HasAdminRecordActions is implemented by an admin controller that registers
+// named record actions for its config_form.yaml recordActions list.
+type HasAdminRecordActions interface {
+	AdminRecordActions() []AdminRecordAction
+}
+
 // AdminPartialData supplies the view model a controller partial template
 // renders (config_list.yaml headerPartial, fields.yaml `type: partial`). name
 // is the partial name; record is the scoped record for a form partial on an