Add HubSpot sync for coupon and newsletter opt-ins

[michaelzick]

Summary

Adds HubSpot subscriber sync to the existing michaelzick.com newsletter and NGU coupon flows. NGU coupon signups still send the coupon email first, and contact-form workbook/newsletter opt-ins still send the contact notification first; HubSpot sync runs afterward as a best-effort integration so CRM issues do not block successful form submissions.

• HubSpot male subscriber sync: upserts contacts by normalized email with gender = Male, lifecyclestage = subscriber, and the configured HubSpot owner.
• Email-only coupon behavior: NGU coupon signups add/update HubSpot contacts without placeholder names or clearing existing first/last names.
• Contact opt-in behavior: contact-form submissions add first/last names to HubSpot only when the workbook/newsletter checkbox is selected.
• michaelzick.com entry notes: creates First entry: michaelzick.com for new contacts and Existing entry: michaelzick.com for existing contacts, skipping duplicate entry notes.
• Non-blocking CRM failures: missing HubSpot env vars or HubSpot API failures are logged with sanitized errors and do not prevent coupon/contact success responses.

Changes

• hubspot-subscriber.ts (new) — server-only HubSpot config, contact upsert, note association, duplicate-note detection, sanitized error handling
• ngu-coupon/route.ts — syncs coupon subscribers to HubSpot after visitor/admin emails send
• contact/route.ts — syncs HubSpot only for workbook/newsletter opt-ins, preserving normal contact form behavior
• server.test.ts — adds coverage for env fallback, normalization, contact create/update, conflict retry, duplicate-note skipping, sanitized failures, and name/no-name request bodies
• AGENTS.md, CLAUDE.md, GEMINI.md — documents HubSpot env vars and subscriber-sync behavior

Test plan

• npm test
• npm run agent-briefs:check
• npm run lint
• npm run typecheck
• npm run check

Created by Codex