Rebrand: Co-op Check-in -> Co-op Survey in user-facing copy

Updates the tool product name across the app UI (header, page title,
section labels, form buttons, success/error states, report stat labels),
README, deployment docs, and the CiviCRM email template guidance.
Custom domain references move from check-in.fci.coop to survey.fci.coop
(DNS update still required).

The underlying CiviCRM "Check-in (organizing)" activity type, custom
group machine names (Check_in_data__organizing_), health-check ids,
and the internal org_engagement_check_in form id are unchanged --
those are CiviCRM contract surfaces, not product copy.

types/form.ts

@@ -203,7 +203,7 @@ export interface FormConfig {
 /**
  * Identifying details for the contact submitting the form, derived from the
  * cid resolved by /api/data. Surfaced as readonly fields in Stage 0 so the
- * person filling out the check-in can confirm who's logged as the submitter.
+ * person filling out the survey can confirm who's logged as the submitter.
  */
 export interface ContactIdentity {
   firstName: string;