/**
 * Shared invariant for manual and template-driven vehicle-seat writes.
 * Callers performing persistence must hold the parent vehicle row lock until
 * their seat insert/update commits.
 */
export declare function assertVehicleChildCapacity({ capacity, existingSeatCount, seatsToAdd, }: {
    capacity: number;
    existingSeatCount: number;
    seatsToAdd: number;
}): void;
export declare function normalizeVehicleSeatDesignation(label: string | null | undefined, flags: Record<string, unknown> | null | undefined): string | null;
export declare function assertVehicleSeatDesignationAvailable({ label, flags, existingSeats, }: {
    label: string | null | undefined;
    flags: Record<string, unknown> | null | undefined;
    existingSeats: ReadonlyArray<{
        label: string | null;
        flags: Record<string, unknown> | null;
    }>;
}): void;