feat: 自动旋转按钮改为播放/暂停图标状态

frontend/public/earth/js/controls.js

@@ -179,11 +179,26 @@ export function resetView(camera) {
 }
 
 function setupRotateControls(camera, earth) {
-  document.getElementById('rotate-toggle').addEventListener('click', function() {
+  const rotateBtn = document.getElementById('rotate-toggle');
+  const tooltip = rotateBtn?.querySelector('.tooltip');
+  
+  function updateRotateIcon() {
+    const isRotating = getAutoRotate();
+    rotateBtn.innerHTML = isRotating ? '⏸️' : '▶️';
+    if (tooltip) {
+      tooltip.textContent = isRotating ? '暂停旋转' : '开始旋转';
+    }
+  }
+  
+  rotateBtn.addEventListener('click', function() {
     toggleAutoRotate();
-    showStatusMessage(autoRotate ? '自动旋转已开启' : '自动旋转已暂停', 'info');
+    const isRotating = getAutoRotate();
+    updateRotateIcon();
+    showStatusMessage(isRotating ? '自动旋转已开启' : '自动旋转已暂停', 'info');
   });
   
+  updateRotateIcon();
+  
   document.getElementById('reset-view').addEventListener('click', function() {
     resetView(camera);
   });