SplashOverlay 抽公共组件 + 进度条配色统一

大厅 / 子游戏之前各有一份 private SplashOverlay：lobby 版含错误态 UI（拉远端
配置失败 splash 上提示重试 / 前往设置）；sub-game 版只有 image + label +
progressView，配色规则不同（width 0.45 vs 0.7，progressTintColor 不设）。

抽到 Source/WebView/SplashOverlay.swift 共用组件：
- 含完整加载 UI + 错误态 UI（sub-game 不调 showError，但保留兜底）
- 进度条 progressTintColor = .black，trackTintColor = .systemGray5（实色浅灰）
  之前 lobby 用 .systemBlue + label.withAlphaComponent(0.15) 半透明轨道，
  黑色填充推过半透明轨道时视觉上像"颜色逐渐加深"；改实色轨道后是干脆的
  "黑滑过灰"，无加深错觉
- progressView.setProgress(animated: true) 保留补间，让快下载也能看到平滑增长

WebContainer / SubGame 删除各自的 private SplashOverlay 类定义，引用同一份。

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

ylgamehall/Source/WebView/SubGameViewController.swift

@@ -364,66 +364,3 @@ extension SubGameViewController: WKNavigationDelegate {
     }
 }
 
-// MARK: - SplashOverlay（与 WebContainerViewController 同款，先就地复制；
-//                       Phase 1.B 后续抽公共组件时合并到 Source/UI/SplashOverlay.swift）
-
-private final class SplashOverlay: UIView {
-
-    private let imageView = UIImageView()
-    private let progressView = UIProgressView(progressViewStyle: .default)
-    private let label = UILabel()
-
-    init() {
-        super.init(frame: .zero)
-        backgroundColor = .black
-
-        // scaleAspectFill：与 LaunchScreen / WebContainer splash 同款全屏覆盖策略
-        // （现代 iPhone 横屏 19.5:9 比 16:9 素材更宽，scaleAspectFit 会左右补大黑边）
-        imageView.contentMode = .scaleAspectFill
-        imageView.image = UIImage(named: "SplashImage")
-        imageView.clipsToBounds = true
-        imageView.translatesAutoresizingMaskIntoConstraints = false
-        addSubview(imageView)
-
-        label.textColor = .white
-        label.font = .systemFont(ofSize: 14, weight: .medium)
-        label.textAlignment = .center
-        label.numberOfLines = 1
-        label.translatesAutoresizingMaskIntoConstraints = false
-        addSubview(label)
-
-        progressView.translatesAutoresizingMaskIntoConstraints = false
-        progressView.isHidden = true
-        addSubview(progressView)
-
-        NSLayoutConstraint.activate([
-            imageView.topAnchor.constraint(equalTo: topAnchor),
-            imageView.bottomAnchor.constraint(equalTo: bottomAnchor),
-            imageView.leadingAnchor.constraint(equalTo: leadingAnchor),
-            imageView.trailingAnchor.constraint(equalTo: trailingAnchor),
-
-            label.centerXAnchor.constraint(equalTo: centerXAnchor),
-            label.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -32),
-            label.leadingAnchor.constraint(greaterThanOrEqualTo: leadingAnchor, constant: 24),
-            label.trailingAnchor.constraint(lessThanOrEqualTo: trailingAnchor, constant: -24),
-
-            progressView.centerXAnchor.constraint(equalTo: centerXAnchor),
-            progressView.bottomAnchor.constraint(equalTo: label.topAnchor, constant: -12),
-            progressView.widthAnchor.constraint(equalTo: widthAnchor, multiplier: 0.45)
-        ])
-    }
-
-    @available(*, unavailable)
-    required init?(coder: NSCoder) { fatalError("SplashOverlay does not support init(coder:)") }
-
-    func update(text: String, progress: Double?) {
-        label.text = text
-        if let p = progress {
-            progressView.isHidden = false
-            progressView.setProgress(Float(p), animated: true)
-        } else {
-            progressView.isHidden = true
-            progressView.setProgress(0, animated: false)
-        }
-    }
-}