ruff

52257b30 - Run file discovery single-threaded in Ruff project benchmarks (#30322)

Run file discovery single-threaded in Ruff project benchmarks (#30322) ## Summary Ruff’s project benchmarks lint and format on one Rayon thread, but file discovery could still start up to 12 workers. The benchmark now sets a single-worker limit for both phases so directory-walk scheduling has less opportunity to affect wall-time and peak-heap measurements. Ruff’s CLI walker also respects `RAYON_NUM_THREADS`, up to its existing cap of 12. ty still gives a positive `TY_MAX_PARALLELISM` precedence and falls back to `RAYON_NUM_THREADS` when the override is invalid. ## Test Plan Ran the resolver tests and cached project benchmarks locally, and verified thread-limit precedence in fresh processes.