- src/utils/atomic-write.js: single shared tmp+fsync+rename writer (exclusive-create 0600, unique tmp names, cleanup-on-failure, best-effort parent-dir fsync after rename for swap durability) - notification-manager: both write paths (load-time canonicalization write-back + saveConfig) converted from plain writeFileSync — a crash mid-write can no longer truncate notifications.json - DC-097/098 test seams migrated to the atomic path; new suite pins syscall discipline (order, wx flags, tmp naming, error cleanup, dir-fsync swallow) - 121 suites / 2768 tests green - Judge: GLM-5.3 cold read grade B/ship (deleg_23f7abad); polish items folded: dir-fsync added, header copy-count corrected. Remaining: migrate invite/user/share-store private _atomicWriteJSON copies as they are touched (queued). URN: pending (recorded post-commit)
