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/RDEPUBReaderSettingsViewController.swift

@@ -12,6 +12,8 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
     var onBrightnessChange: ((CGFloat) -> Void)?
     /// 字号变化回调（pt 值）
     var onFontSizeChange: ((CGFloat) -> Void)?
+    /// 字体变化回调
+    var onFontChoiceChange: ((RDEPUBReaderFontChoice) -> Void)?
     /// 行距倍数变化回调
     var onLineHeightChange: ((CGFloat) -> Void)?
     /// 栏数变化回调
@@ -66,6 +68,7 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
     private let fontValueLabel = UILabel()
     private let decreaseFontButton = UIButton(type: .system)
     private let increaseFontButton = UIButton(type: .system)
+    private let fontChoiceControl = UISegmentedControl(items: RDEPUBReaderFontChoice.allCases.map(\.displayName))
     private let lineHeightControl = UISegmentedControl(items: ["紧凑", "标准", "宽松"])
     private let columnCountControl = UISegmentedControl(items: ["单栏", "双栏"])
     private let displayTypeControl = UISegmentedControl(items: ["仿真", "横滑", "竖滑"])
@@ -103,11 +106,14 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
     }
 
     private func setupNavigationItems() {
-        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "完成", style: .done, target: self, action: #selector(doneAction))
+        let doneItem = UIBarButtonItem(title: "完成", style: .done, target: self, action: #selector(doneAction))
+        doneItem.accessibilityIdentifier = "epub.reader.settings.done"
+        navigationItem.rightBarButtonItem = doneItem
     }
 
     private func setupViews() {
         view.addSubview(scrollView)
+        scrollView.accessibilityIdentifier = "epub.reader.settings.scroll"
         scrollView.translatesAutoresizingMaskIntoConstraints = false
         scrollView.addSubview(contentStack)
         contentStack.translatesAutoresizingMaskIntoConstraints = false
@@ -127,17 +133,26 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
 
         brightnessSlider.minimumValue = 0
         brightnessSlider.maximumValue = 1
+        brightnessSlider.accessibilityIdentifier = "epub.reader.settings.brightness"
         brightnessSlider.addTarget(self, action: #selector(brightnessChanged(_:)), for: .valueChanged)
 
         fontValueLabel.font = UIFont.monospacedDigitSystemFont(ofSize: 16, weight: .semibold)
         fontValueLabel.textAlignment = .center
+        fontValueLabel.accessibilityIdentifier = "epub.reader.settings.font.value"
         fontValueLabel.setContentHuggingPriority(.required, for: .horizontal)
 
         configureFontButton(decreaseFontButton, title: "A-")
         configureFontButton(increaseFontButton, title: "A+")
+        decreaseFontButton.accessibilityIdentifier = "epub.reader.settings.font.decrease"
+        increaseFontButton.accessibilityIdentifier = "epub.reader.settings.font.increase"
         decreaseFontButton.addTarget(self, action: #selector(decreaseFontAction), for: .touchUpInside)
         increaseFontButton.addTarget(self, action: #selector(increaseFontAction), for: .touchUpInside)
 
+        lineHeightControl.accessibilityIdentifier = "epub.reader.settings.lineHeight"
+        fontChoiceControl.accessibilityIdentifier = "epub.reader.settings.font.choice"
+        columnCountControl.accessibilityIdentifier = "epub.reader.settings.columns"
+        displayTypeControl.accessibilityIdentifier = "epub.reader.settings.displayType"
+        fontChoiceControl.addTarget(self, action: #selector(fontChoiceChanged(_:)), for: .valueChanged)
         lineHeightControl.addTarget(self, action: #selector(lineHeightChanged(_:)), for: .valueChanged)
         columnCountControl.addTarget(self, action: #selector(columnCountChanged(_:)), for: .valueChanged)
         displayTypeControl.addTarget(self, action: #selector(displayTypeChanged(_:)), for: .valueChanged)
@@ -149,6 +164,7 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
             button.layer.borderWidth = 1.5
             button.backgroundColor = preset.theme.contentBackgroundColor
             button.accessibilityLabel = preset.title
+            button.accessibilityIdentifier = "epub.reader.settings.theme.\(preset.rawValue)"
             button.addTarget(self, action: #selector(themeButtonAction(_:)), for: .touchUpInside)
             themeButtons.append(button)
             themeStackView.addArrangedSubview(button)
@@ -159,6 +175,7 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
 
         contentStack.addArrangedSubview(makeSection(title: "亮度", content: brightnessSlider))
         contentStack.addArrangedSubview(makeSection(title: "字号", content: makeFontSizeRow()))
+        contentStack.addArrangedSubview(makeSection(title: "字体", content: fontChoiceControl))
         contentStack.addArrangedSubview(makeSection(title: "行距", content: lineHeightControl))
         contentStack.addArrangedSubview(makeSection(title: "分栏", content: columnCountControl))
         contentStack.addArrangedSubview(makeSection(title: "翻页方式", content: displayTypeControl))
@@ -205,6 +222,7 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
 
     private func syncControls() {
         fontValueLabel.text = String(Int(currentConfiguration.fontSize.rounded()))
+        fontChoiceControl.selectedSegmentIndex = RDEPUBReaderFontChoice.allCases.firstIndex(of: currentConfiguration.fontChoice) ?? 0
 
         let lineHeightIndex = lineHeightValues.enumerated().min { abs($0.element - currentConfiguration.lineHeightMultiple) < abs($1.element - currentConfiguration.lineHeightMultiple) }?.offset ?? 1
         lineHeightControl.selectedSegmentIndex = lineHeightIndex
@@ -239,7 +257,7 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
             button.backgroundColor = theme.toolBackgroundColor
         }
 
-        [lineHeightControl, columnCountControl, displayTypeControl].forEach { control in
+        [fontChoiceControl, lineHeightControl, columnCountControl, displayTypeControl].forEach { control in
             control.backgroundColor = theme.toolBackgroundColor
             if #available(iOS 13.0, *) {
                 control.selectedSegmentTintColor = theme.toolControlTextColor.withAlphaComponent(0.14)
@@ -288,6 +306,15 @@ final class RDEPUBReaderSettingsViewController: UIViewController {
         onFontSizeChange?(nextValue)
     }
 
+    @objc private func fontChoiceChanged(_ control: UISegmentedControl) {
+        let choices = RDEPUBReaderFontChoice.allCases
+        let index = max(0, min(control.selectedSegmentIndex, choices.count - 1))
+        let choice = choices[index]
+        guard choice != currentConfiguration.fontChoice else { return }
+        currentConfiguration.fontChoice = choice
+        onFontChoiceChange?(choice)
+    }
+
     @objc private func lineHeightChanged(_ control: UISegmentedControl) {
         let index = max(0, min(control.selectedSegmentIndex, lineHeightValues.count - 1))
         let value = lineHeightValues[index]