feat: 交互协调器拆分、附件提示、暗色图片适配、选区放大镜及文档清理

- 拆分 ContentDelegates/TextContentView 为独立协调器（InteractionCoordinator、LocationResolution、ExternalLinks、AttachmentTooltip）
- 新增 RDEPUBAttachmentTooltipView/OverlayView 附件气泡提示
- 新增 RDEPUBDarkImageAdjuster 暗色模式图片亮度适配
- 新增 RDEPUBSelectionLoupeView 选区放大镜
- 新增 MetadataParseWorker/CancellationController 元数据解析取消机制
- 重构 PresentationRuntime/PaginationCoordinator 精简职责
- 优化 ChapterLoader/WarmupOrchestrator 异步章节加载
- CFI 模块微调与 NoteModels 更新
- 清理冗余文档，更新架构/UML/业务逻辑文档

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

Sources/RDReaderView/EPUBUI/ReaderController/ChapterRuntime/RDEPUBChapterRuntimeStore.swift

@@ -32,6 +32,10 @@ final class RDEPUBChapterRuntimeStore {
 
     private let cfiMapLock = NSLock()
 
+    private var pendingChapterLoadSpineIndices: Set<Int> = []
+
+    private let pendingChapterLoadLock = NSLock()
+
     init() {
 
         imageCache.countLimit = 50
@@ -146,6 +150,25 @@ final class RDEPUBChapterRuntimeStore {
         buildingLock.unlock()
     }
 
+    func beginPendingChapterLoad(for spineIndex: Int) -> Bool {
+        pendingChapterLoadLock.lock()
+        defer { pendingChapterLoadLock.unlock() }
+        return pendingChapterLoadSpineIndices.insert(spineIndex).inserted
+    }
+
+    func endPendingChapterLoad(for spineIndex: Int) {
+        pendingChapterLoadLock.lock()
+        pendingChapterLoadSpineIndices.remove(spineIndex)
+        pendingChapterLoadLock.unlock()
+    }
+
+    func hasPendingChapterLoad(for spineIndex: Int) -> Bool {
+        pendingChapterLoadLock.lock()
+        let hasPendingLoad = pendingChapterLoadSpineIndices.contains(spineIndex)
+        pendingChapterLoadLock.unlock()
+        return hasPendingLoad
+    }
+
     func beginBuildingCFIMap(for spineIndex: Int) -> Bool {
         cfiMapLock.lock()
         defer { cfiMapLock.unlock() }
@@ -166,5 +189,8 @@ final class RDEPUBChapterRuntimeStore {
         cfiMapLock.lock()
         buildingCFIMapSpineIndices.removeAll()
         cfiMapLock.unlock()
+        pendingChapterLoadLock.lock()
+        pendingChapterLoadSpineIndices.removeAll()
+        pendingChapterLoadLock.unlock()
     }
 }