[clbotdev]

Part of #79. Closes #68.

What

• Docs: new "Migrate to SendLit" section.
  • migrate/overview covers the 7 steps: export, connect the ESP, domain authentication, import, signup forms and welcome sequence, web archive, test then first broadcast. It ends with a pre-switch checklist: mailing address, SPF/DKIM/DMARC, Reply-To, matching counts, unsubscribe link, replacing old forms, warm-up, and keeping the old tool until healthy.
  • migrate/beehiiv, migrate/substack and migrate/mailchimp each document that tool's export steps, checked against the beehiiv and Mailchimp help centres, and its status → SendLit mapping.
  • The guides are linked from getting-started (overview, and first-broadcast now links import and the guides), from the contacts import docs, and from the import dialog.
• Importer fix (found while writing the Mailchimp guide). Mailchimp exports one CSV per status with no status column, and an empty status means subscribed. So importing unsubscribed_… or cleaned_… would have subscribed those contacts.
  • When no column is mapped as status, the dialog now asks "Everyone in this file is…".
  • It pre-selects the answer from Mailchimp's file names using the new guessImportStatusFromFileName in api-contract.
  • Mailchimp's quoted TAGS ("A","B") are unquoted.
  • deactivated maps to unsubscribed.
  • toImportRows moved to apps/web/lib/contact-import.ts, with tests.

Verification

• check.sh (format, lint, typecheck, 715 API tests, web tests incl. new contact-import.test.ts, contract tests incl. file-name guessing). apps/docs next build passes; the section can't use an index page, because the static export collides with the folder.
• Browser E2E (6/6) on Mailchimp-format files (Email Address, OPTIN_TIME, quoted TAGS, no status column):
  1. The dialog links to the guides.
  2. The subscribed_… file pre-selects Subscribed and imports with tags Early access, VIP and the original signup date.
  3. The unsubscribed_… file imports unsubscribed.
  4. The cleaned_… file imports with 2 suppressed, as hard_bounce suppressions.
  5. The status can be overridden, and the question disappears once a column is mapped as status.
  6. The built docs show the section, all three guides and the link from first-broadcast.