Update enterprise contact form to new growth API endpoint

[Copilot]

Migrates the enterprise contact form submission from the legacy /feedback/sales/enterprise endpoint to the new /conversations/enterprises growth endpoint.

Changes

• Endpoint: /feedback/sales/enterprise → /conversations/enterprises
• Removed: subject param (not part of new API)
• Added: platform: 'appwrite' param
• UTM params (utmSource, utmReferral, utmMedium) already aligned with new spec via getReferrerAndUtmSource()

-const response = await fetch(`${PUBLIC_GROWTH_ENDPOINT}/feedback/sales/enterprise`, {
+const response = await fetch(`${PUBLIC_GROWTH_ENDPOINT}/conversations/enterprises`, {
     body: JSON.stringify({
-        email,
-        subject: companyName,
-        cloudEmail,
-        companyName,
+        firstName,
+        lastName,
+        email,
+        message: useCase,
         companyName,
         companySize,
         companyWebsite,
-        firstName,
-        lastName,
-        message: useCase,
+        cloudEmail,
+        platform: 'appwrite',
         ...getReferrerAndUtmSource()
     })
 });

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.