feat: redesign homepage with triptych process + admin image management

- Redesign Hero section with new copy focused on the triptych offering
- Add Process component (replaces System) with zigzag layout for 3 pillars:
  Google Maps reviews, managed Facebook, converting website
- Redesign AboutMe with orange background and stats row
- Add admin panel for managing site image URLs (replaces Sanity dependency)
- Create site_images API routes and Supabase-backed storage with defaults
- Update FAQ to reference built-in admin panel
- Add site_images table type to database types
- Pass images prop through homepage components

https://claude.ai/code/session_01V8YAjpqRQ3bfBYsABYsEgo

components/admin/AdminShell.tsx

@@ -40,6 +40,15 @@ const navItems = [
       </svg>
     ),
   },
+  {
+    label: "Images du site",
+    href: "/admin/images",
+    icon: (
+      <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.5} d="M2.25 15.75l5.159-5.159a2.25 2.25 0 013.182 0l5.159 5.159m-1.5-1.5l1.409-1.409a2.25 2.25 0 013.182 0l2.909 2.909m-18 3.75h16.5a1.5 1.5 0 001.5-1.5V6a1.5 1.5 0 00-1.5-1.5H3.75A1.5 1.5 0 002.25 6v12a1.5 1.5 0 001.5 1.5zm10.5-11.25h.008v.008h-.008V8.25zm.375 0a.375.375 0 11-.75 0 .375.375 0 01.75 0z" />
+      </svg>
+    ),
+  },
 ];
 
 export default function AdminShell({ children, adminName, adminEmail }: AdminShellProps) {