Bulk verification, sender reputation, and an in-app Verify page
New /verify page for interactive single-email and bulk (up to 500 at once, with CSV export) checks — the first human-usable UI for the verification engine. Added domain-level sender-reputation scoring from this system's own verification history. Fixed a bug where failed webhook deliveries never actually retried, and closed a GDPR erasure gap (OAuth tokens and MFA credentials are now cleared on account deletion, not just the profile fields).