72e2ef6721
Backend for #738. Real TOTP 2FA for admin accounts, all roles incl. super_admin (closes #735). - mfaService: otplib TOTP; AES-256-GCM encryption of the secret at rest (key derived from MFA_ENCRYPTION_KEY or JWT_SECRET); bcrypt-hashed, single-use recovery codes; otpauth URI + QR. - Migration 151: adds two_factor_recovery_codes + two_factor_enrolled_at (secret/enabled columns already existed from legacy 016). - Enrollment endpoints (behind adminAuth, per-user): GET /mfa/status, POST /mfa/{setup,enable,disable,recovery-codes}. Disable/regenerate require a current code so a hijacked session can't strip 2FA. - Login challenge: /admin/login returns {mfaRequired, mfaToken} (no session) when 2FA is on; /admin/login/mfa exchanges a TOTP or recovery code for the session. Lockout counter is NOT reset until the second factor passes, so MFA brute-force is rate-limited too. - CLI break-glass: scripts/reset-admin-mfa.js --email <e> | --all --yes, audit-logged, matches reset-admin-password.js convention. - Docs + optional MFA_ENCRYPTION_KEY env. Verified end-to-end on a live backend: enroll (super_admin), challenge, TOTP + single-use recovery login, disable, and CLI reset.