* feat(email): add deliverability guards to reduce waitlist bounces
Analyzed 1,276 bounced waitlist emails and found typos (gamil.com),
disposable domains (passmail, guerrillamail), offensive submissions,
and non-existent domains account for the majority.
Four layers of protection:
- Frontend: mailcheck.js typo suggestions on email blur
- API: MX record check via Cloudflare DoH, disposable domain
blocklist, offensive pattern filter, typo-TLD blocklist
- Webhook: api/resend-webhook.js captures bounce/complaint events,
stores in Convex emailSuppressions table, checked before sending
- Tooling: import script for bulk-loading existing bounced emails
* fix(email): address review - auth, retry, CSV parsing
1. Security: Convert suppress/bulkSuppress/remove to internalMutation.
Webhook now runs as Convex httpAction (matching Dodo pattern) with
direct access to internal mutations. Bulk import uses relay shared
secret. Only isEmailSuppressed remains public (read-only query).
2. Retry: Convex httpAction returns 500 on any mutation failure so
Resend retries the webhook instead of silently losing bounce events.
3. CSV: Replace naive comma-split with RFC 4180 parser that handles
quoted fields. Import script now calls Convex HTTP action
authenticated via RELAY_SHARED_SECRET instead of public mutation.
* fix(email): make isEmailSuppressed internal, check inside mutation
Move suppression check into registerInterest:register mutation
(same transaction, no extra round-trip). Remove public query
entirely so no suppression data is exposed to browser clients.
* test(email): add coverage for validation, CSV parser, and suppressions
- 19 tests for validateEmail: disposable domains, offensive patterns,
typo TLDs, MX fail-open, case insensitivity, privacy relay allowance
- 7 tests for parseCsvLine: RFC 4180 quoting, escaped quotes, empty
fields, Resend CSV format with angle brackets and commas
- 11 Convex tests for emailSuppressions: suppress idempotency, case
normalization, bulk dedup, remove, and registerInterest integration
(emailSuppressed flag in mutation return)
