Phase 1.14.e：webView didFinish 后 0.3s 淡出 splash

把 WKNavigationDelegate.didFinish 里的 splash.isHidden = true 换成
UIView.animate(withDuration: 0.3) 渐变 alpha=0 + completion 内
removeFromSuperview，避免渲染瞬间硬切，也让 view 层级在大厅起来后
完全干净（无空持有的 splash 占位）。

BuildProject 通过

Plan 进度已勾选（§5 Phase 1.14.e + §8）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ylgamehall/Source/WebView/WebContainerViewController.swift

@@ -223,9 +223,13 @@ public final class WebContainerViewController: UIViewController {
 
 extension WebContainerViewController: WKNavigationDelegate {
     public func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
-        // Phase 1.14.d 阶段：直接隐藏 splash（无动画）
-        // Phase 1.14.e 将替换为 UIView.animate(0.3) 淡出 + removeFromSuperview
-        splash.isHidden = true
+        // H5 大厅已经渲染完毕，此时把 splash 从 0.3s 内淡出再 removeFromSuperview，
+        // 避免黑屏闪烁也避免后续 superview 再持有这层不必要的视图。
+        UIView.animate(withDuration: 0.3, animations: { [weak self] in
+            self?.splash.alpha = 0
+        }, completion: { [weak self] _ in
+            self?.splash.removeFromSuperview()
+        })
     }
 }