fix: 改进 Flutter Web 加载指示器隐藏逻辑

使用五种方式确保加载指示器被正确隐藏：
- Flutter 第一帧渲染完成事件
- Flutter 引擎初始化检查
- 10秒超时保护
- 页面加载后检查 Flutter 视图
- 定期轮询检查 Flutter 视图

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flutter_monisuo/build/web/.last_build_id

@@ -1 +1 @@
-cd059bcd8df9e9b2b7bfff5ee9fb7ba7
+2b1d2ed877ca1d041aef5d6561fbfcf5

flutter_monisuo/build/web/flutter_bootstrap.js

@@ -37,6 +37,6 @@ _flutter.buildConfig = {"engineRevision":"e4b8dca3f1b4ede4c30371002441c88c12187e
 
 _flutter.loader.load({
   serviceWorkerSettings: {
-    serviceWorkerVersion: "1409326861" /* Flutter's service worker is deprecated and will be removed in a future Flutter release. */
+    serviceWorkerVersion: "1994875870" /* Flutter's service worker is deprecated and will be removed in a future Flutter release. */
   }
 });

flutter_monisuo/build/web/index.html

@@ -103,15 +103,66 @@
 
   <!-- 隐藏加载指示器 -->
   <script>
-    window.addEventListener('flutter-first-frame', function() {
+    // 防止重复隐藏
+    var loadingHidden = false;
+
+    function hideLoading() {
+      if (loadingHidden) return;
+      loadingHidden = true;
+
       var loading = document.getElementById('loading');
       if (loading) {
-        loading.classList.add('loading-hidden');
+        loading.style.opacity = '0';
+        loading.style.transition = 'opacity 0.3s ease-out';
         setTimeout(function() {
-          loading.remove();
+          if (loading && loading.parentNode) {
+            loading.parentNode.removeChild(loading);
+          }
         }, 300);
       }
+    }
+
+    // 方式1: Flutter 第一帧渲染完成（最可靠的方式）
+    window.addEventListener('flutter-first-frame', hideLoading);
+
+    // 方式2: 监听 Flutter 引擎初始化完成
+    if (window._flutter) {
+      window._flutter.loaderDidLoad = true;
+    }
+
+    // 方式3: 超时保护（10秒后强制隐藏）
+    var timeoutId = setTimeout(hideLoading, 10000);
+
+    // 方式4: 页面完全加载后检查（5秒后）
+    window.addEventListener('load', function() {
+      setTimeout(function() {
+        // 检查 Flutter 应用是否已渲染
+        var flutterView = document.querySelector('flutter-view') ||
+                          document.querySelector('flt-glass-pane');
+        if (flutterView) {
+          hideLoading();
+        } else {
+          // 如果还没渲染，再等3秒
+          setTimeout(hideLoading, 3000);
+        }
+      }, 5000);
     });
+
+    // 方式5: 定期检查 Flutter 视图是否已存在
+    var checkInterval = setInterval(function() {
+      var flutterView = document.querySelector('flutter-view') ||
+                        document.querySelector('flt-glass-pane');
+      if (flutterView && flutterView.offsetWidth > 0) {
+        clearInterval(checkInterval);
+        clearTimeout(timeoutId);
+        hideLoading();
+      }
+    }, 500);
+
+    // 15秒后清除检查间隔
+    setTimeout(function() {
+      clearInterval(checkInterval);
+    }, 15000);
   </script>
 
   <!-- vConsole 调试控制台 - 仅在开发环境启用 -->

flutter_monisuo/web/index.html

@@ -103,15 +103,66 @@
 
   <!-- 隐藏加载指示器 -->
   <script>
-    window.addEventListener('flutter-first-frame', function() {
+    // 防止重复隐藏
+    var loadingHidden = false;
+
+    function hideLoading() {
+      if (loadingHidden) return;
+      loadingHidden = true;
+
       var loading = document.getElementById('loading');
       if (loading) {
-        loading.classList.add('loading-hidden');
+        loading.style.opacity = '0';
+        loading.style.transition = 'opacity 0.3s ease-out';
         setTimeout(function() {
-          loading.remove();
+          if (loading && loading.parentNode) {
+            loading.parentNode.removeChild(loading);
+          }
         }, 300);
       }
+    }
+
+    // 方式1: Flutter 第一帧渲染完成（最可靠的方式）
+    window.addEventListener('flutter-first-frame', hideLoading);
+
+    // 方式2: 监听 Flutter 引擎初始化完成
+    if (window._flutter) {
+      window._flutter.loaderDidLoad = true;
+    }
+
+    // 方式3: 超时保护（10秒后强制隐藏）
+    var timeoutId = setTimeout(hideLoading, 10000);
+
+    // 方式4: 页面完全加载后检查（5秒后）
+    window.addEventListener('load', function() {
+      setTimeout(function() {
+        // 检查 Flutter 应用是否已渲染
+        var flutterView = document.querySelector('flutter-view') ||
+                          document.querySelector('flt-glass-pane');
+        if (flutterView) {
+          hideLoading();
+        } else {
+          // 如果还没渲染，再等3秒
+          setTimeout(hideLoading, 3000);
+        }
+      }, 5000);
     });
+
+    // 方式5: 定期检查 Flutter 视图是否已存在
+    var checkInterval = setInterval(function() {
+      var flutterView = document.querySelector('flutter-view') ||
+                        document.querySelector('flt-glass-pane');
+      if (flutterView && flutterView.offsetWidth > 0) {
+        clearInterval(checkInterval);
+        clearTimeout(timeoutId);
+        hideLoading();
+      }
+    }, 500);
+
+    // 15秒后清除检查间隔
+    setTimeout(function() {
+      clearInterval(checkInterval);
+    }, 15000);
   </script>
 
   <!-- vConsole 调试控制台 - 仅在开发环境启用 -->