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/EPUBTextRendering/Pagination/RDEPUBPageBreakPolicy.swift

@@ -166,80 +166,6 @@ struct RDEPUBPageBreakPolicy {
 
     // MARK: - 语义边界查找
 
-    /// 在指定范围内查找最优的语义分页点（pageBreakBefore / pageBreakAfter）。
-    func preferredSemanticBoundary(
-        in range: NSRange,
-        minimumEnd: Int,
-        factory: RDEPUBCoreTextPageFrameFactory
-    ) -> (location: Int, trigger: String)? {
-        guard let safeRange = factory.clampedRange(range), safeRange.length > 0 else {
-            return nil
-        }
-        var boundary: (location: Int, trigger: String)?
-        attributedString.enumerateAttribute(.rdPageSemanticHints, in: safeRange) { value, attributeRange, stop in
-            guard let rawValue = value as? String else { return }
-            let hints = rawValue
-                .split(separator: ",")
-                .compactMap { RDEPUBTextSemanticHint(rawValue: String($0)) }
-            guard !hints.isEmpty else { return }
-
-            if hints.contains(.pageBreakBefore),
-               attributeRange.location > safeRange.location,
-               attributeRange.location >= minimumEnd {
-                boundary = (attributeRange.location, RDEPUBTextSemanticHint.pageBreakBefore.rawValue)
-                stop.pointee = true
-                return
-            }
-
-            let attributeEnd = attributeRange.location + attributeRange.length
-            if hints.contains(.pageBreakAfter),
-               attributeEnd > minimumEnd,
-               attributeEnd < safeRange.location + safeRange.length {
-                boundary = (attributeEnd, RDEPUBTextSemanticHint.pageBreakAfter.rawValue)
-                stop.pointee = true
-                return
-            }
-        }
-        return boundary
-    }
-
-    /// 查找附件边界：只有块级附件才触发分页。
-    func preferredAttachmentBoundary(
-        in range: NSRange,
-        minimumEnd: Int,
-        factory: RDEPUBCoreTextPageFrameFactory
-    ) -> Int? {
-        guard let safeRange = factory.clampedRange(range), safeRange.length > 0 else {
-            return nil
-        }
-        var boundary: Int?
-        attributedString.enumerateAttribute(.rdPageAttachmentKind, in: safeRange) { value, attributeRange, stop in
-            guard value != nil else { return }
-
-            let location = attributeRange.location
-            let placement = factory.attachmentPlacement(at: location)
-            let blockKind = factory.blockKind(at: location)
-
-            let isBlockLevelAttachment: Bool
-            switch placement {
-            case .centered:
-                isBlockLevelAttachment = true
-            case .inline, .baseline:
-                isBlockLevelAttachment = false
-            case nil:
-                isBlockLevelAttachment = blockKind == .attachment
-            }
-            guard isBlockLevelAttachment else { return }
-
-            let boundaryRange = factory.blockRange(at: location) ?? factory.paragraphRange(containing: location)
-            if boundaryRange.location > safeRange.location, boundaryRange.location >= minimumEnd {
-                boundary = boundaryRange.location
-                stop.pointee = true
-            }
-        }
-        return boundary
-    }
-
     /// 查找 pageRelate 跨页关联边界。
     func preferredPageRelateBoundary(
         after range: NSRange,