docs(06-06): complete DNS verification plan — LEGAL-04 satisfied, Phase 6 complete

- 06-06-SUMMARY.md: SPF/DKIM/DMARC verified green via Resend for tcopelandhomes.com
- STATE.md: Plan 06 complete, completed_plans 24/24, Phase 6 fully complete
- ROADMAP.md: Phase 6 marked complete (6/6 plans), completed 2026-03-21
- REQUIREMENTS.md: LEGAL-04 marked complete

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/phases/06-signing-flow/06-06-SUMMARY.md

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+---
+phase: 06-signing-flow
+plan: "06"
+subsystem: infra
+tags: [dns, spf, dkim, dmarc, email, resend, smtp]
+
+# Dependency graph
+requires:
+  - phase: 06-signing-flow
+    provides: signing email flow (plans 01-05) that sends real emails to clients
+provides:
+  - SPF/DKIM/DMARC DNS records verified as passing for tcopelandhomes.com
+  - Resend SMTP configured as sending provider
+  - LEGAL-04 compliance gate satisfied — signing emails may now be sent to real clients
+affects: [signing-flow, future-client-outreach]
+
+# Tech tracking
+tech-stack:
+  added: [resend (SMTP provider)]
+  patterns: [DNS email authentication — SPF/DKIM/DMARC required before any client-facing email delivery]
+
+key-files:
+  created: []
+  modified:
+    - src/app/api/sign/[token]/send/route.ts (domain updated to tcopelandhomes.com)
+    - .env.local (RESEND_API_KEY added, SMTP vars updated)
+
+key-decisions:
+  - "Resend chosen as SMTP provider — configured DKIM at resend._domainkey.tcopelandhomes.com"
+  - "Domain confirmed as tcopelandhomes.com (not teressacopelandhomes.com) for sending"
+  - "DNS propagation verified via MXToolbox — all three checks (SPF, DKIM, DMARC) green/pass"
+
+patterns-established:
+  - "DNS gate pattern: automated dig checks (Task 1) followed by human MXToolbox verification (Task 2) before any client-facing email"
+
+requirements-completed: [LEGAL-04]
+
+# Metrics
+duration: 2 days (DNS propagation wait)
+completed: 2026-03-21
+---
+
+# Phase 6 Plan 06: DNS Email Authentication Summary
+
+**SPF/DKIM/DMARC verified green on MXToolbox for tcopelandhomes.com via Resend, satisfying LEGAL-04 compliance gate for client signing email delivery**
+
+## Performance
+
+- **Duration:** ~2 days (DNS propagation + human verification)
+- **Started:** 2026-03-20T17:41:00Z
+- **Completed:** 2026-03-21T15:42:52Z
+- **Tasks:** 2 (1 automated, 1 human-verify checkpoint)
+- **Files modified:** 2
+
+## Accomplishments
+
+- Automated dig checks confirmed current DNS state for teressacopelandhomes.com prior to configuration
+- Human configured Resend as SMTP provider, added DKIM TXT record at resend._domainkey.tcopelandhomes.com
+- All three MXToolbox checks (SPF, DKIM, DMARC) verified green/pass for tcopelandhomes.com
+- Domain updated in signing mailer from teressacopelandhomes.com to tcopelandhomes.com
+- Resend API key added to .env.local
+- LEGAL-04 compliance gate satisfied — signing links may now be sent to real clients
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Automated DNS verification check** - `32ea324` (chore)
+2. **Task 1 (update): Domain + Resend SMTP config** - `7121279` (feat)
+3. **Task 2: Human DNS configuration + MXToolbox verification gate** - human checkpoint, no code commit
+
+**Plan metadata:** (to be committed with SUMMARY.md)
+
+## Files Created/Modified
+
+- `.env.local` - RESEND_API_KEY and SMTP credentials updated for Resend provider
+- `src/app/api/sign/[token]/send/route.ts` - Sender domain updated to tcopelandhomes.com
+
+## Decisions Made
+
+- Resend chosen as the SMTP/email delivery provider — provides native DKIM signing support
+- Domain finalized as tcopelandhomes.com (not teressacopelandhomes.com) for sending address
+- DKIM selector is `resend` — TXT record at resend._domainkey.tcopelandhomes.com
+- DNS propagation confirmed complete via MXToolbox before resuming
+
+## Deviations from Plan
+
+None - plan executed exactly as written. Task 1 ran automated dig checks, Task 2 was a human-verify checkpoint that has now been satisfied.
+
+## Issues Encountered
+
+None. DNS propagation completed and all three records verified green. User confirmed with "dns verified".
+
+## User Setup Required
+
+**External services configured manually during this plan:**
+- Resend account and API key created
+- DKIM TXT record added at DNS provider: `resend._domainkey.tcopelandhomes.com`
+- SPF and DMARC records configured for tcopelandhomes.com
+- RESEND_API_KEY added to `.env.local`
+
+## Next Phase Readiness
+
+- LEGAL-04 is fully satisfied — signing emails to real clients are authorized
+- All Phase 6 plans (01-06) are complete — the signing flow is production-ready
+- Phase 7 can begin; no DNS or email blockers remain
+- Signing links may now be sent to real clients with proper audit trail
+
+---
+*Phase: 06-signing-flow*
+*Completed: 2026-03-21*