feat: add SVG icon and generate PNG icons

- Added a new SVG icon file for the application.
- Created a manifest.json file for the web app with relevant metadata.
- Introduced package-lock.json to manage dependencies.
- Implemented a script to generate PNG icons from the SVG source using sharp.

index.html

@@ -28,6 +28,12 @@
   <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
   <meta name="apple-mobile-web-app-title" content="Finger Chooser">
 
+  <!-- Icons & Manifest -->
+  <link rel="manifest" href="manifest.json">
+  <link rel="apple-touch-icon" href="icons/apple-touch-icon.png">
+  <link rel="icon" type="image/png" sizes="32x32" href="icons/favicon-32.png">
+  <link rel="icon" type="image/svg+xml" href="icons/icon.svg">
+
   <link rel="stylesheet" href="css/style.css">
 
   <script type="application/ld+json">