Get Email Debug

2026-08-27: diagnostic for the "Key was issued but the confirmation email failed to send" error AJ hit on the self-serve Intelligence API signup flow. services/email_service.py's EmailService.send() only ever logs print(f"Email error: {e}") to server stdout on failure -- not visible from the outside, and this whole SMTP path can't be exercised from the sandbox (no route to Railway's outbound network / real SMTP creds). This endpoint surfaces exactly which step fails and why, without needing Railway CLI log access.

Step 1 (always runs, no side effect): reports whether each required env var is SET (never the actual secret value) plus the non-secret SMTP_HOST/SMTP_PORT values, then attempts connect -> starttls -> login against the real configured SMTP server, reporting the exact exception and which of those three steps it happened at. This alone diagnoses the overwhelming majority of "email failed" cases (missing env var, wrong host/port, revoked app password, provider blocking the IP) with zero risk of actually sending anything.

Step 2 (opt-in via send_test=true&test_to=you@example.com): only after step 1's login succeeds, sends one real test email so AJ can confirm delivery end-to-end (not just that auth works) -- e.g. Namecheap/Gmail can accept a login but still silently drop mail past that point.

2026-08-27: now branches on RESEND_API_KEY first (see services/ email_service.py's module docstring -- Railway blocks outbound SMTP below its Pro plan, confirmed via this exact endpoint's connect: "FAILED: timed out" result against mail.privateemail.com:587). When RESEND_API_KEY is set, this checks Resend's HTTP API instead (GET /domains, which validates the key without sending anything) and skips the SMTP connect/starttls/login walk entirely, since EmailService.send itself would do the same -- this endpoint should diagnose whichever path send() actually takes, not a path it no longer uses.