/**
 * Collect per-file git activity in one `git log` pass, scoped by the same pathspecs as the index.
 * Renames are not followed (counts accrue under the path's current name — fine for grounding).
 * Returns an empty map when the root is not a git repo, so metadata is always optional.
 * @param {string} root
 * @param {string[]} [pathspecs]
 * @returns {Map<string, GitSig>}
 */
export function collectGitSig(root: string, pathspecs?: string[]): Map<string, GitSig>;
export type GitSig = {
    /**
     * number of commits that touched the file
     */
    commits: number;
    /**
     * unix time (seconds) of the most recent such commit, or null
     */
    lastCommit: number | null;
};