The 20-concurrent-processes append test in src/lib/file-lock.test.ts dropped one append on a CI runner (19/20 landed, run 2026-07-07 on PR #248) and passed on rerun - runner-contention flake, not a product bug (the lock protocol itself is O_EXCL + ABA-guarded).
Options: bump per-process lock wait headroom under CI, reduce to 10 processes, or add test-level retry. Keep the zero-lost-writes assertion - it is the point of the test.
The 20-concurrent-processes append test in src/lib/file-lock.test.ts dropped one append on a CI runner (19/20 landed, run 2026-07-07 on PR #248) and passed on rerun - runner-contention flake, not a product bug (the lock protocol itself is O_EXCL + ABA-guarded).
Options: bump per-process lock wait headroom under CI, reduce to 10 processes, or add test-level retry. Keep the zero-lost-writes assertion - it is the point of the test.