feat(auth): enhance password reset logging and Resend response tracking

feat(phase-7): implement FastAPI backend, React SPA frontend, and Docker deployment

fix(auth): enforce uniform response time floor and random jitter to neutralize network timing side-channels

fix(auth): harden password reset identity resolution, email uniqueness, timing protection, and TTL index

feat(auth): add secure rate-limited password reset flow with Resend email integration

feat(phase-6): implement rate limiting, daily search quotas, and brute-force lockout

fix(phase-5): enforce credential authentication gates and eliminate hardcoded JWT secrets

feat(phase-5): implement cryptographic JWT authentication and dual-key MongoDB user isolation