- uploadEvidenceFile: validate file type via file-type magic bytes, reject client-supplied MIME, derive extension from detected type, upload ArrayBuffer - getEscalationThreshold: use setUTCHours instead of setHours so date-only ISO strings (always UTC midnight) compare consistently in any timezone - Tests: mock file-type, update upload expectation to ArrayBuffer Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01CPf5Rc8QPx6V8KLEEgfKEQ