/**
 * Migration helpers extracted from `reconcile-service.ts`
 * 800-line cap. Behaviour-preserving verbatim move.
 */
/**
 *
 * Move the legacy runtime files at:
 *   - `.peaks/.session.json`
 *   - `.peaks/.active-skill.json`
 *   - `.peaks/sop-state/`
 * into their new canonical home at:
 *   - `.peaks/_runtime/session.json`
 *   - `.peaks/_runtime/active-skill.json`
 *   - `.peaks/_runtime/sop-state/`
 *
 * Behavior:
 *   - Idempotent: re-running on a tree that is already on the new
 *     layout produces `migratedFiles: []`.
 *   - Best-effort: uses `fs.renameSync` (atomic on POSIX, best-effort
 *     on Windows) and falls back to `copyFileSync` + `unlinkSync` if
 *     rename throws (e.g. cross-device move on Windows). Errors are
 *     collected per file and returned in the `errors` array so the
 *     reconcile envelope can surface them without blocking the rest of
 *     the migration.
 *   - Creates `.peaks/_runtime/` on demand if any of the old paths
 *     are present.
 *
 * @returns `{ migratedFiles, errors }`. `migratedFiles` lists the
 *   *old* relative paths (e.g. `.peaks/.session.json`) that were
 *   successfully moved, in move order. `errors` lists per-file
 *   failures with the old path and a human-readable message.
 */
export declare function migrateOldRuntimeState(projectRoot: string): {
    migratedFiles: string[];
    errors: Array<{
        path: string;
        message: string;
    }>;
};
/**
 *
 * Move the legacy per-session sub-agent state files at:
 *   - `.peaks/_runtime/<sid>/system/subagent-progress.json`
 *   - `.peaks/_runtime/<sid>/system/progress-spawn.json`
 * into the new canonical home at:
 *   - `.peaks/_sub_agents/<sid>/subagent-progress.json`
 *   - `.peaks/_sub_agents/<sid>/progress-spawn.json`
 *
 * Behavior:
 *   - Idempotent: re-running on a tree that is already on the new layout
 *     produces `migratedFiles: []`.
 *   - Best-effort: uses `fs.renameSync` and falls back to `copyFileSync +
 *     unlinkSync` if rename throws (e.g. cross-device move on Windows).
 *   - Empty `<sid>/system/` dir removal (R-2 guard): the legacy `system/`
 *     subdir is only removed when it has zero other files, so a tree where
 *     the user had unrelated content in `system/` is left untouched.
 *   - New-path-wins: when both old and new files exist, the old file is
 *     removed (the new path is authoritative).
 *
 * Walks every discovered session — not just the canonical one — so a user
 * with 6 pre-migration sessions gets all of them migrated in one reconcile
 * pass.
 *
 * @returns `{ migratedFiles, errors }`. `migratedFiles` lists the *old*
 *   relative paths (e.g. `.peaks/_runtime/<sid>/system/subagent-progress.json`) that
 *   were successfully moved. `errors` lists per-file failures.
 */
export declare function migrateSubAgentState(projectRoot: string): {
    migratedFiles: string[];
    errors: Array<{
        path: string;
        message: string;
    }>;
};