Add leaderboard component to UI and API endpoint to fetch player rankings.

public/styles_home.css

@@ -136,4 +136,52 @@ button.logout {
     height: 100vh;
     background: transparent;
     pointer-events: none;
+}
+
+.leaderboard {
+    position: absolute;
+    top: 100px;
+    left: 20px;
+    background: rgba(0, 0, 0, 0.7);
+    border: 2px solid #0f0;
+    border-radius: 10px;
+    padding: 20px;
+    width: 200px;
+    color: #0f0;
+    font-family: monospace;
+    box-shadow: 0 0 10px #0f0;
+    z-index: 1;
+}
+
+.leaderboard h3 {
+    margin-top: 0;
+    font-size: 18px;
+    text-align: center;
+    text-shadow: 0 0 5px #0f0;
+}
+
+.leaderboard ul {
+    list-style: none;
+    padding: 0;
+    margin: 0;
+}
+
+.leaderboard li {
+    margin: 5px 0;
+    font-size: 14px;
+    text-shadow: 0 0 3px #0f0;
+}
+
+.leaderboard li.you {
+    font-weight: bold;
+    color: #ff0;
+    text-shadow: 0 0 5px #ff0;
+}
+
+.your-rank {
+    margin-top: 10px;
+    font-size: 14px;
+    color: #fff;
+    text-align: center;
+    text-shadow: 0 0 3px #0f0;
 }