feat(reader): 增强阅读器功能与 UI 测试支持

- 新增字体选择（系统/宋体/圆体/等宽）与暗色图片柔化配置
- 文本选择改为自定义手势+操作栏（拷贝/高亮/批注）
- 添加 accessibilityIdentifier 支持自动化 UI 测试
- 新增 UITests 覆盖阅读器打开/关闭、工具栏、设置面板、批注等
- 添加 Demo 测试用 EPUB 书源（宝山辽墓材料与释读）
- 新增文档：UI 自动化测试、功能开发计划、阅读器规划

Sources/RDReaderView/EPUBUI/Settings/RDEPUBReaderConfiguration.swift

@@ -9,6 +9,51 @@ public enum RDEPUBTextRenderingEngine: Equatable {
     case dtCoreText
 }
 
+// MARK: - 阅读字体
+
+/// 阅读器内置字体选项。
+/// 第一版优先使用系统授权字体，后续可扩展为 bundle 内置字体注册。
+public enum RDEPUBReaderFontChoice: String, Codable, CaseIterable, Equatable {
+    /// 系统默认无衬线字体
+    case system
+    /// 系统衬线字体
+    case serif
+    /// 系统圆体字体
+    case rounded
+    /// 系统等宽字体
+    case monospaced
+
+    public var displayName: String {
+        switch self {
+        case .system:
+            return "系统"
+        case .serif:
+            return "宋体"
+        case .rounded:
+            return "圆体"
+        case .monospaced:
+            return "等宽"
+        }
+    }
+
+    public func font(ofSize size: CGFloat) -> UIFont {
+        switch self {
+        case .system:
+            return UIFont.systemFont(ofSize: size)
+        case .serif:
+            let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
+                .withDesign(.serif) ?? UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
+            return UIFont(descriptor: descriptor, size: size)
+        case .rounded:
+            let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
+                .withDesign(.rounded) ?? UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
+            return UIFont(descriptor: descriptor, size: size)
+        case .monospaced:
+            return UIFont.monospacedSystemFont(ofSize: size, weight: .regular)
+        }
+    }
+}
+
 // MARK: - 阅读器配置
 
 /// EPUB 阅读器的完整配置结构体
@@ -21,6 +66,8 @@ public struct RDEPUBReaderConfiguration: Equatable {
     public var fontSize: CGFloat
     /// 行距倍数，默认 1.6（即行距为字号的 1.6 倍）
     public var lineHeightMultiple: CGFloat
+    /// 正文字体，默认系统字体
+    public var fontChoice: RDEPUBReaderFontChoice
     /// 栏数，默认单栏
     public var numberOfColumns: Int
     /// 栏间距，默认 20pt
@@ -50,6 +97,10 @@ public struct RDEPUBReaderConfiguration: Equatable {
 
     /// 当前阅读主题（浅色/深色/护眼等），默认 .light
     public var theme: RDEPUBReaderTheme
+    /// 暗色主题下是否柔化正文图片，降低夜间阅读刺眼感
+    public var darkImageAdjustmentEnabled: Bool
+    /// 暗色主题图片柔化混合比例，0 表示不处理，推荐 0.12 ~ 0.2
+    public var darkImageBlendRatio: CGFloat
     /// 固定布局的适配模式：按页适配或按宽度适配
     public var fixedLayoutFit: RDEPUBFixedLayoutFit
     /// 固定布局的跨页模式：自动/单页/双页
@@ -63,6 +114,7 @@ public struct RDEPUBReaderConfiguration: Equatable {
     /// - Parameters:
     ///   - fontSize: 正文字号，默认 15pt
     ///   - lineHeightMultiple: 行距倍数，默认 1.6
+    ///   - fontChoice: 正文字体，默认系统字体
     ///   - displayType: 翻页模式，默认 .pageCurl
     ///   - landscapeDualPageEnabled: 横屏双页，默认 true
     ///   - showsTableOfContents: 显示目录入口，默认 true
@@ -71,12 +123,15 @@ public struct RDEPUBReaderConfiguration: Equatable {
     ///   - reflowableContentInsets: 流式排版内边距
     ///   - fixedContentInset: 固定布局内边距
     ///   - theme: 阅读主题，默认 .light
+    ///   - darkImageAdjustmentEnabled: 暗色主题下是否柔化正文图片
+    ///   - darkImageBlendRatio: 暗色主题图片柔化混合比例
     ///   - fixedLayoutFit: 固定布局适配模式
     ///   - fixedLayoutSpreadMode: 固定布局跨页模式
     ///   - textRenderingEngine: 文本渲染引擎
     public init(
         fontSize: CGFloat = 15,
         lineHeightMultiple: CGFloat = 1.6,
+        fontChoice: RDEPUBReaderFontChoice = .system,
         numberOfColumns: Int = 1,
         columnGap: CGFloat = 20,
         displayType: RDReaderView.DisplayType = .pageCurl,
@@ -87,12 +142,15 @@ public struct RDEPUBReaderConfiguration: Equatable {
         reflowableContentInsets: UIEdgeInsets = UIEdgeInsets(top: 40, left: 16, bottom: 40, right: 16),
         fixedContentInset: UIEdgeInsets = .zero,
         theme: RDEPUBReaderTheme = .light,
+        darkImageAdjustmentEnabled: Bool = true,
+        darkImageBlendRatio: CGFloat = 0.15,
         fixedLayoutFit: RDEPUBFixedLayoutFit = .page,
         fixedLayoutSpreadMode: RDEPUBFixedLayoutSpreadMode = .automatic,
         textRenderingEngine: RDEPUBTextRenderingEngine = .dtCoreText
     ) {
         self.fontSize = fontSize
         self.lineHeightMultiple = lineHeightMultiple
+        self.fontChoice = fontChoice
         self.numberOfColumns = max(1, numberOfColumns)
         self.columnGap = max(0, columnGap)
         self.displayType = displayType
@@ -103,6 +161,8 @@ public struct RDEPUBReaderConfiguration: Equatable {
         self.reflowableContentInsets = reflowableContentInsets
         self.fixedContentInset = fixedContentInset
         self.theme = theme
+        self.darkImageAdjustmentEnabled = darkImageAdjustmentEnabled
+        self.darkImageBlendRatio = max(0, min(0.35, darkImageBlendRatio))
         self.fixedLayoutFit = fixedLayoutFit
         self.fixedLayoutSpreadMode = fixedLayoutSpreadMode
         self.textRenderingEngine = textRenderingEngine