统一后台状态入口为 onAndroidLifecycle

- 移除冗余的 onNativeBackground/onNativeForeground
- onAndroidLifecycle 支持 pause/resume/background/foreground/stop/start 多种状态值
- Android WebView 统一调用: evaluateJavascript("onAndroidLifecycle('pause')")

web/mobile.html

@@ -263,12 +263,17 @@ function setBackground(bg) {
   }
 }
 
-// 1) 供 Android 原生调用: webView.evaluateJavascript("onAndroidLifecycle('pause')")
+// 1) 供 Android WebView 原生调用(统一入口):
+//    webView.evaluateJavascript("onAndroidLifecycle('pause')", null);
+//    webView.evaluateJavascript("onAndroidLifecycle('resume')", null);
 window.onAndroidLifecycle = function(state) {
-  setBackground(state === 'pause' || state === 'background' || state === 'stop');
+  const s = String(state).toLowerCase();
+  if (s === 'pause' || s === 'paused' || s === 'background' || s === 'stop') {
+    setBackground(true);
+  } else if (s === 'resume' || s === 'resumed' || s === 'foreground' || s === 'start') {
+    setBackground(false);
+  }
 };
-window.onNativeBackground = function() { setBackground(true); };
-window.onNativeForeground = function() { setBackground(false); };
 
 // 2) 浏览器 Page Visibility API
 document.addEventListener('visibilitychange', () => {