s3fs-fuse-0001: StatCache::RawGetChildStats() dedup uses std::find()
on std::vector<std::string> inside loop over childmap. O(N*M) on every
readdir() and rename_directory() call. Fix: unordered_set for O(1)
lookup. MEDIUM severity, 13.8x at N=2000/M=1000.
MOAD-0002 (intertangle): globals are config-only, set at startup.
Subsystems (stat cache, fd cache, curl) are properly isolated
behind singleton + mutex. CLEAN.
MOAD-0003 (leaked context): no thread_local usage found. CLEAN.
MOAD-0004 (logged secret): all credential logging uses
mask_sensitive_string(). insecure_logging is opt-in and deprecated.
CLEAN.
MOAD-0005 (thundering herd): stat cache uses std::mutex properly.
curl handle pool uses lock_guard. No unprotected cache paths. CLEAN.
