- Wire COOKIE_DOMAIN env var into BetterAuth cookie config
- Add URL validation for TRUSTED_ORIGINS (rejects non-HTTP, invalid URLs)
- Include original parse error in validateRedirectUri error message
- Distinguish infrastructure errors from auth errors in verifySession
(Prisma/connection errors now propagate as 500 instead of masking as 401)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>