/**
 * Async file-system walker used by nexus_optimize_tokens and nexus_hypertune_max.
 *
 * Extracted from mcp.ts (Phase 3 split) to keep each file under 1500 LOC.
 * Uses BFS with pLimit(8) concurrency — no sync FS calls, no per-entry stat.
 *
 * Fast path: `git ls-files` for repos (< 300 ms even on large codebases).
 * Fall back to walkDir only when not inside a git repository.
 */
/**
 * Recursively walk `root`, returning all file paths.
 * Directories in SKIP are never descended into.
 */
export declare function walkDir(root: string): Promise<string[]>;
/**
 * Enumerate TypeScript source files via `git ls-files` (fast path) or
 * recursive walkDir (fallback for non-git directories).
 *
 * `git ls-files` completes in < 300 ms even on large repos; walkDir on a
 * repo with thousands of files can exceed the 25 s MCP handler timeout.
 * Cache keyed on cwd + top-level directory mtime so repeated calls are free.
 */
export declare function scanSourceFiles(cwd: string, scanCache: Map<string, {
    mtimeMs: number;
    files: string[];
}>): Promise<string[]>;
