feat: EPUB 阅读器搜索、选中注释、书签 chrome 状态及大量重构优化

- 新增 RDEPUBReaderSearchCoordinator 与 RDEPUBSelectionState 管理搜索和选中状态
- 新增 BookmarkChromeStateTests、NavigationBackwardTests、SelectionAnnotateTests 等 UI 测试
- 新增多个边界测试 epub 样本（损坏结构、空归档、缺失文件、流式外链验证）
- 重构阅读器 chrome 状态管理，统一 tool bar 与 search bar 交互
- 优化大书分页缓存策略（RDEPUBChapterSummaryDiskCache、RDEPUBPageCountCache）
- 移除废弃的 RDEPUBLocationConverter 和 RDEPUBPageBreakPolicy
- 更新 epub-bridge.js 与 JS bridge 通信协议
- 全面更新现有 UI 测试以适配新的 helper 和状态管理

Sources/RDReaderView/EPUBUI/TextPage/RDEPUBTextContentView.swift

@@ -14,6 +14,11 @@ protocol RDEPUBTextContentViewDelegate: AnyObject {
         didRequestSelectionAction action: RDEPUBAnnotationMenuAction,
         selection: RDEPUBSelection?
     )
+    func textContentView(
+        _ contentView: RDEPUBTextContentView,
+        didActivateAttachmentText text: String,
+        sourceRect: CGRect
+    )
     func textContentView(
         _ contentView: RDEPUBTextContentView,
         didRequestHighlightActions highlight: RDEPUBHighlight,
@@ -33,6 +38,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
     private var currentSelection: RDEPUBSelection?
     private var menuSelection: RDEPUBSelection?
     private var currentHighlights: [RDEPUBHighlight] = []
+    private var currentSearchState: RDEPUBSearchState?
     weak var delegate: RDEPUBTextContentViewDelegate?
 
 #if canImport(DTCoreText)
@@ -188,6 +194,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
         currentSelection = nil
         menuSelection = nil
         currentHighlights = highlights
+        currentSearchState = searchState
         selectionController.clearSelection(renderView: coreTextRenderView)
         contentInsets = configuration.reflowableContentInsets
         backgroundColor = configuration.theme.contentBackgroundColor
@@ -244,14 +251,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
         overlayView.configure(page: page, selectionColor: overlayView.selectionColor, snapshot: interactionController.snapshot)
 #if canImport(DTCoreText)
         backgroundOverlayView.configure(page: page, selectionColor: overlayView.selectionColor, snapshot: interactionController.snapshot)
-        let (bgDecorations, fgDecorations) = overlayView.buildDecorations(
-            page: page,
-            highlights: [],
-            searchState: searchState,
-            interactionController: interactionController
-        )
-        backgroundOverlayView.applyDecorations(bgDecorations)
-        overlayView.applyDecorations(fgDecorations)
 #endif
         updateAccessibilityDecorationSummary()
 
@@ -262,6 +261,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
     func clearSelection() {
         currentSelection = nil
         menuSelection = nil
+        currentSearchState = nil
         panGestureRecognizer.isEnabled = false
         selectionController.clearSelection(renderView: coreTextRenderView)
         overlayView.clearSelection()
@@ -487,6 +487,17 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
         interactionController.configure(layoutFrame: layoutFrame, page: page)
         overlayView.updateSnapshot(interactionController.snapshot)
         backgroundOverlayView.updateSnapshot(interactionController.snapshot)
+
+        if let page = currentPage {
+            let (bgDecorations, fgDecorations) = overlayView.buildDecorations(
+                page: page,
+                highlights: [],
+                searchState: currentSearchState,
+                interactionController: interactionController
+            )
+            backgroundOverlayView.applyDecorations(bgDecorations)
+            overlayView.applyDecorations(fgDecorations)
+        }
     }
 #endif
 
@@ -539,6 +550,11 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
             clearSelection()
             return
         }
+        if let attachmentText = attachmentText(at: point),
+           let sourceRect = attachmentSourceRect(at: point, fallbackPoint: point) {
+            delegate?.textContentView(self, didActivateAttachmentText: attachmentText, sourceRect: sourceRect)
+            return
+        }
         guard let highlight = highlight(at: point),
               let sourceRect = highlightSourceRect(for: highlight, fallbackPoint: point) else {
             return
@@ -621,6 +637,41 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
         return overlayView.convert(fallbackRect, to: self)
     }
 
+    private func attachmentText(at point: CGPoint) -> String? {
+        guard let page = currentPage else { return nil }
+        guard let attachmentRange = interactionController.snapshot?.attachment(at: point)?.stringRange else {
+            return nil
+        }
+        guard page.chapterContent.length > attachmentRange.location else {
+            return nil
+        }
+        let attachment = page.chapterContent.attribute(.attachment, at: attachmentRange.location, effectiveRange: nil)
+
+#if canImport(DTCoreText)
+        if let textAttachment = attachment as? DTTextAttachment,
+           let altText = (textAttachment.attributes["alt"] as? String)?
+            .trimmingCharacters(in: .whitespacesAndNewlines),
+           !altText.isEmpty {
+            return altText
+        }
+#endif
+
+        if let fileAttachment = attachment as? NSTextAttachment,
+           let altText = fileAttachment.accessibilityLabel?.trimmingCharacters(in: .whitespacesAndNewlines),
+           !altText.isEmpty {
+            return altText
+        }
+        return nil
+    }
+
+    private func attachmentSourceRect(at point: CGPoint, fallbackPoint: CGPoint) -> CGRect? {
+        if let attachmentRect = interactionController.snapshot?.attachment(at: point)?.frame {
+            return overlayView.convert(attachmentRect, to: self)
+        }
+        let fallbackRect = CGRect(origin: fallbackPoint, size: CGSize(width: 1, height: 1))
+        return overlayView.convert(fallbackRect, to: self)
+    }
+
     override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
         if gestureRecognizer === panGestureRecognizer {
             return selectionController.isSelecting
@@ -633,7 +684,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
                 return true
             }
             let point = tapGestureRecognizer.location(in: overlayView)
-            return highlight(at: point) != nil
+            return attachmentText(at: point) != nil || highlight(at: point) != nil
         }
         return true
     }