Replace placeholder icons with custom image and fix PWA manifest colors

Regenerated all icons (favicon, apple-touch-icon, pwa-192, pwa-512) from
manual-icon.png using ImageMagick. Updated manifest and meta theme-color
from black to the app's blue (#a8d5e8), and added start_url to the manifest.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

vite.config.ts

@@ -12,9 +12,10 @@ export default defineConfig({
         name: 'Black 7',
         short_name: 'Black 7',
         description: 'Scoring app for Last Panther',
-        theme_color: '#000000',
-        background_color: '#000000',
+        theme_color: '#a8d5e8',
+        background_color: '#a8d5e8',
         display: 'standalone',
+        start_url: '/',
         icons: [
           {
             src: 'pwa-192x192.png',