feat(ECR-013A): Admin RBAC 实现并 Closed

角色权限、RequirePermission、/me permissions 与 migration 000015；
Reviewer Approve → Closed。Next：ECR-013B Contract Definition。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/repository/admin_repo.go

@@ -32,12 +32,15 @@ func (r *AdminRepo) CountAccounts(ctx context.Context) (int, error) {
 	return n, err
 }
 
-// CreateAccount inserts an admin account.
+// CreateAccount inserts an admin account with seeded super_admin role.
 func (r *AdminRepo) CreateAccount(ctx context.Context, username, hash string) (uuid.UUID, error) {
 	var id uuid.UUID
 	err := r.Pool.QueryRow(ctx, `
-		INSERT INTO admin_accounts(username, password_hash)
-		VALUES ($1,$2) RETURNING id`, username, hash).Scan(&id)
+		INSERT INTO admin_accounts(username, password_hash, role_id)
+		VALUES (
+			$1, $2,
+			(SELECT id FROM admin_roles WHERE name = 'super_admin' LIMIT 1)
+		) RETURNING id`, username, hash).Scan(&id)
 	return id, err
 }