Add Waitlist to Lovable App

Add a waitlist system to my Lovable app.

REQUIREMENTS:
1. Create a waitlist signup form with email input and "Join the Waitlist" button. Show total waitlist count for social proof.
2. After signup, show a confirmation page with: their position number, a unique referral link, and social sharing buttons (Twitter, LinkedIn, email).
3. Track referrals: when someone signs up via a referral link, credit the referrer. Move referrers up in the queue (e.g., +1 position per referral).
4. Display the user's current position and number of referrals on a status page accessible via their unique link.
5. Add an admin page to view all waitlist signups, send invites in batches, and export the list as CSV.
6. Prevent duplicate signups by checking email uniqueness.
7. Add a simple landing page above the fold with the value proposition and waitlist form.

DATABASE:
- "waitlist" table: id, email, referral_code (unique), referred_by (FK to waitlist.id), referral_count, position, status (waiting/invited/joined), created_at
- RLS: Public can insert. Only admins can read all rows.

SECURITY:
- Rate limit signups to prevent spam (max 3 signups per IP per hour).
- Validate email format and reject disposable email domains.
- Never expose other users' emails in the referral system.