Add player functionality with HLS support and API integration

- Implemented a new Player class in player.js to handle audio playback, including HLS support using hls.js.
- Created a shared API module in api.js for making HTTP requests with proper error handling.
- Added DOM utility functions in dom.js for creating and clearing elements.
- Introduced WebSocket connection handling in ws.js for real-time updates.
- Developed a comprehensive CSS stylesheet for styling the application, including a high-contrast theme.

web/shared/ws.js

@@ -0,0 +1,22 @@
+export function connectWs(onMessage) {
+  let ws, retry = 0, closed = false;
+  function open() {
+    const proto = location.protocol === 'https:' ? 'wss' : 'ws';
+    ws = new WebSocket(`${proto}://${location.host}/ws`);
+    ws.addEventListener('open', () => { retry = 0; });
+    ws.addEventListener('message', (ev) => {
+      try { onMessage(JSON.parse(ev.data)); } catch {}
+    });
+    ws.addEventListener('close', () => {
+      if (closed) return;
+      retry = Math.min(retry + 1, 6);
+      setTimeout(open, 500 * 2 ** retry);
+    });
+    ws.addEventListener('error', () => ws.close());
+  }
+  open();
+  return {
+    send(msg) { if (ws?.readyState === WebSocket.OPEN) ws.send(JSON.stringify(msg)); },
+    close()   { closed = true; ws?.close(); }
+  };
+}