Add Testimonials Section to Lovable App

Add a testimonials system to my Lovable app.

REQUIREMENTS:
1. Create a testimonials display section on the home page showing approved testimonials in a carousel or grid. Each testimonial shows: client photo (or initials avatar), name, company/title, star rating, and quote.
2. Create a "Share Your Experience" form where clients can submit testimonials: name, email, company, role, rating (1-5 stars), testimonial text, and optional photo upload.
3. New submissions save to Supabase with status="pending". Only status="approved" testimonials appear on the site.
4. Create an admin approval page listing pending testimonials with Approve, Edit, and Reject buttons.
5. Display testimonials in a responsive grid: 3 columns on desktop, 1 on mobile. Include a "View All" link if showing a subset on the homepage.
6. Add random rotation so different testimonials show on each page load.

DATABASE:
- "testimonials" table: id, name, email, company, role, rating, content, photo_url, status (pending/approved/rejected), featured, created_at
- RLS: Anyone can insert (submit). Only admins can update status. Public can read approved only.

SECURITY:
- Sanitize testimonial text to prevent XSS.
- Rate limit submissions to 1 per email per day.