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.

app/layout.tsx

@@ -28,7 +28,7 @@ const body = Open_Sans({
 });
 
 export const metadata: Metadata = {
-  title: "Co-op Check-in · Food Co-op Initiative",
+  title: "Co-op Survey · Food Co-op Initiative",
   description:
     "Update your co-op's progress through the FCI organizing Framework. A survey for food co-ops in development.",
   robots: { index: false, follow: false }, // Form pages are tokenized; not for crawlers.