/**
 * Ownership registry for `.pi/skills/` mirrors.
 *
 * Records which skill names AIWS has mirrored into `.pi/skills/` so that
 * stale cleanup (`pruneStalePiSkills`) can distinguish AIWS-managed mirrors
 * from user-custom directories. Persisted locally (`.pi/` is gitignored).
 */
export declare const PI_SKILL_REGISTRY_FILE = ".aiws-sync.json";
export interface PiSkillRegistry {
    version: 1;
    updatedAt: string;
    managed: string[];
}
/**
 * Read the pi-skill ownership registry. Returns [] when missing or unparsable
 * (safe failure — callers must not delete anything they cannot attribute).
 */
export declare function readPiSkillRegistry(piDir: string): Promise<string[]>;
/** Atomically write the pi-skill ownership registry. */
export declare function writePiSkillRegistry(piDir: string, managed: string[]): Promise<void>;
/**
 * Read the names of first-level directories under `dir` (e.g. `.pi/skills/`
 * or template `.agents/skills/`). Returns [] when the dir is missing.
 */
export declare function listFirstLevelDirs(dir: string): Promise<string[]>;
/**
 * Compare two directories recursively (same rel file set + identical bytes).
 * Used to decide whether a `.pi/skills/<name>/` mirror is a pure copy of the
 * template dir (safe to prune) or a user-diverged override (keep).
 */
export declare function dirTreesEqual(a: string, b: string): Promise<boolean>;
/**
 * Clean up `.pi/skills/<name>/` mirrors that are no longer needed.
 *
 * Two cases are pruned:
 *  1. Redundant — the name still exists in the template's `.agents/skills/`;
 *     Pi (>=0.84) auto-discovers project `.agents/skills/` dirs directly, so a
 *     same-name `.pi/skills/` mirror only causes a skill-name collision at pi
     startup. Pruned when the mirror is byte-identical to the template dir.
 *  2. Stale — recorded in the ownership registry but the skill left the
 *     template; removed as before.
 *
 * Safety rules:
 *  - Redundant pruning requires the mirror to be byte-identical to the
 *    template dir (a pure mirror). Diverged copies are kept with a warning.
 *  - Stale pruning only touches names present in the ownership registry
 *    (`.aiws-sync.json`); unregistered dirs are treated as user-custom and
 *    never deleted.
 *  - Deleted dirs are backed up file-by-file into an independent BackupSession
 *    (`aiws rollback` restores them).
 *  - dryRun prints `would remove` and does not modify anything.
 */
export declare function pruneStalePiSkills(workspaceRoot: string, templateDir: string | undefined, dryRun: boolean): Promise<void>;