export type NodeId = string;
export type Node = {
    id: NodeId;
    x: number;
    y: number;
    width: number;
    height: number;
    /** Rotation in degrees, clockwise. Defaults to 0 when omitted. */
    rotation?: number;
    /** Corner radius: either uniform number or per-corner radii. Defaults to 0 when omitted. */
    cornerRadius?: number | {
        tl: number;
        tr: number;
        br: number;
        bl: number;
    };
    /**
     * Optional logical parent for grouping. If set, this node is considered a child of `parentId`.
     * Invariants:
     *  - parent chain must be acyclic (no cycles)
     *  - `parentId` references an existing node id when non-null
     *  - `parentId` must not equal this node's id
     *
     * MVP note: groups are logical only (no container geometry). Moving a parent moves all descendants.
     */
    parentId?: NodeId | null;
};