fix: resolve mock portal hydration error on staging

[kevinrutledge]

Developer

Kevin Rutledge

What changed?

Split the mock portal into a server component wrapper + client component to fix React hydration error #418 on the Vercel staging site.

The mock portal was a "use client" component that checked process.env.STAGING, but non-NEXT_PUBLIC_ env vars are undefined in the browser. The server rendered the form (saw STAGING=true), the client rendered "not available" (STAGING was undefined), causing a hydration mismatch.

The fix follows the existing server/client pattern used throughout the codebase (e.g. home/page.tsx -> home-content.tsx):

• page.tsx is now a server component with the STAGING guard
• mock-portal-content.tsx is the client component with all the form logic

How to test

1. Run npm test - 237 tests pass
2. Run npm run build - succeeds
3. Deploy to staging - /dev/mock-portal loads without hydration error
4. On production (without STAGING=true) - shows "Not available in production"

Checklist

• Code works and is readable
• Tested locally
• Commits follow conventional commits
• Assigned reviewers