Add generated PNG icons and icon generator script

- icon-192.png
- icon-512.png
- apple-touch-icon.png
- icon-maskable.png
- generate-icons.js script

frontend/generate-icons.js

@@ -0,0 +1,40 @@
+const sharp = require('sharp');
+const fs = require('fs');
+const path = require('path');
+
+const svgBuffer = fs.readFileSync(path.join(__dirname, 'public/icon-192.svg'));
+
+// icon-192.png
+sharp(svgBuffer)
+  .resize(192, 192)
+  .png()
+  .toFile('public/icon-192.png')
+  .then(() => console.log('Created icon-192.png'));
+
+// icon-512.png
+sharp(svgBuffer)
+  .resize(512, 512)
+  .png()
+  .toFile('public/icon-512.png')
+  .then(() => console.log('Created icon-512.png'));
+
+// apple-touch-icon.png (180x180)
+sharp(svgBuffer)
+  .resize(180, 180)
+  .png()
+  .toFile('public/apple-touch-icon.png')
+  .then(() => console.log('Created apple-touch-icon.png'));
+
+// icon-maskable.png (512x512 with padding for safe area)
+sharp(svgBuffer)
+  .resize(384, 384) // 75% of 512 for safe area
+  .extend({
+    top: 64,
+    bottom: 64,
+    left: 64,
+    right: 64,
+    background: { r: 27, g: 26, b: 85, alpha: 1 } // #1B1A55
+  })
+  .png()
+  .toFile('public/icon-maskable.png')
+  .then(() => console.log('Created icon-maskable.png'));