acquireServerLock's bare catch treated EVERY failure as 'another process
holds the lock' — a missing state dir, EACCES, or ENOSPC read as permanent
phantom contention with nothing to debug. Now only EEXIST is contention:
ENOENT self-heals with one mkdirSecure retry, everything else throws
ServerLockError carrying the real errno, and the stale-lock unlink/retry
loop is depth-capped so it can't livelock. Fork's five-case test ported.
Ported from time-attack/gstack (GStack 2).
Co-authored-by: Sina Matian <sina@time-attack.dev>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Garry Tan