web: mark-led OG/Twitter image + PNG apple-touch-icon

The OG image was an unreadable shrunken hero at card size; replace it
with a centered mark-first design (big green shape, large wordmark,
single tagline). Safari cannot use SVG for apple-touch-icon and fell
back to a letter tile — point the icons config at the file-convention
apple-icon.png, now the green mark on white (180x180).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Web/autopilot-monitor-web/app/layout.tsx

@@ -80,7 +80,9 @@ export const metadata: Metadata = {
   icons: {
     icon: "/icon.svg",
     shortcut: "/icon.svg",
-    apple: "/icon.svg",
+    // Safari cannot use SVG for apple-touch-icon; must be an opaque PNG
+    // (served by the app/apple-icon.png file convention).
+    apple: "/apple-icon.png",
   },
 };