feat: Add player entity with WASD/space controls and spawn functionality

styles.css

@@ -39,6 +39,18 @@ body {
     background-color: #ff9800;
 }
 
+#spawn-player-btn {
+    background-color: #4CAF50;
+    color: white;
+    font-weight: bold;
+    padding: 10px 15px;
+    margin-left: 10px;
+}
+
+#spawn-player-btn:hover {
+    background-color: #45a049;
+}
+
 .navigation {
     display: flex;
 }