feat: /v1/role list, get, create, update and delete. Reassign members on delete. Write-time validation (ValidateGrants, duplicates, typed keys against real content types). Name uniqueness (role_name_taken), role_locked, role_has_members, role_conflict on version mismatch. No-escalation: nobody grants a permission they don't hold, and roles.edit_owner_only guards the Owner role. Activity events for role changes. Typed-key exposure in /auth/me. Cleanup of typed rows when a content type is deleted. | Backend only. Will carry the deferred ListGrants decision.

internal/infrastructure/useCases/DeleteRole.go

@@ -0,0 +1,69 @@
+package useCases
+
+import (
+	"RenewCMS/internal/domain/audit"
+	"RenewCMS/internal/domain/contenttype"
+	"RenewCMS/internal/domain/role"
+	"RenewCMS/internal/domain/user"
+	"context"
+)
+
+type DeleteRoleUseCase struct {
+	roles        role.Repository
+	users        user.Repository
+	contentTypes contenttype.Repository
+	recorder     audit.Recorder
+	viewer       roleViewer
+}
+
+type DeleteRoleCommand struct {
+	Caller ContentCaller
+	ID     uint32
+}
+
+func NewDeleteRoleUseCase(roles role.Repository, users user.Repository, contentTypes contenttype.Repository, recorder audit.Recorder) *DeleteRoleUseCase {
+	return &DeleteRoleUseCase{roles: roles, users: users, contentTypes: contentTypes, recorder: recorder, viewer: roleViewer{roles, users, contentTypes}}
+}
+
+func (u *DeleteRoleUseCase) Delete(ctx context.Context, command DeleteRoleCommand) error {
+	target, err := u.roles.Get(command.ID)
+	if err != nil {
+		return err
+	}
+	if err := u.check(command.Caller, target); err != nil {
+		return err
+	}
+
+	event := audit.NewEvent(audit.ActionRoleDelete, audit.CategoryRoles)
+	event.Target = roleTarget(target)
+	event.Params[audit.ParamMembers] = 0
+	if err := u.roles.Delete(target.ID); err != nil {
+		recordRoleWriteFailure(ctx, u.recorder, event, err)
+		return err
+	}
+	u.recorder.Record(ctx, event)
+	return nil
+}
+
+func (u *DeleteRoleUseCase) check(caller ContentCaller, target role.Role) error {
+	if err := ensureEditable(target); err != nil {
+		return err
+	}
+	if err := ensureNotBuiltIn(target); err != nil {
+		return err
+	}
+	if err := ensureNotOwnRole(u.roles, u.users, caller, target); err != nil {
+		return err
+	}
+	if err := ensureCovered(caller, u.contentTypes, target); err != nil {
+		return err
+	}
+	members, err := u.viewer.members(target.ID)
+	if err != nil {
+		return err
+	}
+	if members > 0 {
+		return role.ErrRoleHasMembers
+	}
+	return nil
+}