/**
 * Pure line-level diff via Longest Common Subsequence (M14 ADR D1 — zero
 * dependency, keeps the registry copy-pasteable; no `diff`/`@pierre/diffs`).
 * Suitable for the design-system case (prompts / JSON, < ~500 lines);
 * O(n·m) time. A row is `eq` (unchanged), `del` (only in old), or `add`
 * (only in new). Line numbers are honest: `del` has no rightNo, `add` has no
 * leftNo. Deterministic, total — never throws.
 */
export type DiffRowKind = "eq" | "del" | "add";
export interface DiffRow {
    kind: DiffRowKind;
    text: string;
    /** 1-based line number in the old text (absent for `add`). */
    leftNo?: number;
    /** 1-based line number in the new text (absent for `del`). */
    rightNo?: number;
}
/**
 * Diff `oldText` against `newText` at line granularity. Returns the aligned
 * sequence of rows (eq / del / add) in reading order. `del` before `add` when a
 * line is replaced.
 */
export declare function diffLines(oldText: string, newText: string): DiffRow[];