/**
 * Backend migration — upgrades state backend across allowed transitions.
 *
 * Supported migrations:
 * - local → orphan
 * - local → two-layer
 * - worktree → orphan
 * - worktree → two-layer
 * - orphan ↔ two-layer (both write to the squad-state orphan branch via different layers)
 *
 * In addition to flipping the `stateBackend` key in `.squad/config.json`, this
 * function MIGRATES pre-existing working-tree state (`decisions.md`,
 * `agents/<name>/history.md`) onto the squad-state orphan branch when moving
 * from a working-tree backend to an orphan-storage backend, so post-upgrade
 * agents can read pre-upgrade content (UPGRADE-NO-MIGRATION fix).
 */
/** Best-effort: ensure the squad-state orphan branch exists. Returns true on success. */
export declare function ensureOrphanBranch(dest: string): boolean;
/**
 * Migrate the state backend for an existing squad project.
 *
 * Fixes:
 *   - UPGRADE-FLAG-IGNORED: writes the new `stateBackend` value into config.json
 *     via JSON-aware merge (never textual append → avoids Bug E duplicates).
 *   - UPGRADE-NO-MIGRATION: when moving from a working-tree backend to an
 *     orphan-storage backend, carries existing decisions.md and agent histories
 *     onto the squad-state orphan branch so post-upgrade agents see prior state.
 *   - WI-1: re-installs the full hook set (including new pre-commit/post-commit).
 */
export declare function migrateStateBackend(dest: string, target: string): Promise<void>;
/**
 * INSIDER3-INIT-LEAK fix: when `squad init --state-backend orphan|two-layer`
 * runs, the SDK still hand-writes mutable state files (decisions.md and each
 * agent's history.md) into the working tree because it has no knowledge of the
 * future backend choice. This helper, invoked by the CLI immediately after the
 * orphan branch is created, lifts those mutable files onto the squad-state
 * orphan branch and removes them from the working tree so post-init agents
 * read state exclusively through the runtime bridge.
 *
 * Source-of-truth hierarchy preserved: static files (team.md, charters,
 * ceremonies.md, casting/*, templates/*) are NEVER touched — only mutable
 * state (decisions.md, agents/<n>/history.md) migrates.
 *
 * Returns the relative paths of files that were migrated + removed.
 */
export declare function liftInitMutableStateOntoOrphan(dest: string): string[];
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