Add Pydantic model_validator to ReceiptWitnessSettings that fails fast
if session_encryption_key is missing or a placeholder value. Conditional
validation for resend_api_key when notifications_enabled=true.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Wrap int(timestamp) in try/except to return False instead of raising
ValueError on empty/invalid timestamp, which was causing a 500 error
instead of the intended 406.
Also add tests for empty timestamp (→ 406) and GET /inbound/email (→ 405).
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Paperclip