feat(reader): 实现大书快速进入与增量分页路径

- PaginationCoordinator: 新增 textReflowable 快速进入路径，支持增量章节构建
  与 staged 合并策略，避免整书一次性构建的主线程阻塞
- TextBookBuilder: 重构为支持单章构建与增量合并模式
- ChapterPageCounter: 优化分页计数逻辑，支持章节级分页缓存
- PageFrameFactory: 新增 CoreText 页面帧工厂，提升排版性能
- ReaderContext/ReaderRuntime: 适配增量分页状态管理

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Sources/RDReaderView/EPUBUI/RDEPUBReaderChapterListController.swift

@@ -30,12 +30,15 @@ final class RDEPUBReaderChapterListController: UITableViewController {
 
     override func viewDidLoad() {
         super.viewDidLoad()
+        view.accessibilityIdentifier = "epub.reader.toc.panel"
+        tableView.accessibilityIdentifier = "epub.reader.toc.table"
         tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
         tableView.tableFooterView = UIView(frame: .zero)
         tableView.backgroundColor = theme.contentBackgroundColor
         navigationController?.navigationBar.tintColor = theme.toolControlTextColor
         navigationController?.navigationBar.barTintColor = theme.toolBackgroundColor
         navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: theme.toolControlTextColor]
+        navigationController?.navigationBar.accessibilityIdentifier = "epub.reader.toc.navbar"
     }
 
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
@@ -62,4 +65,4 @@ final class RDEPUBReaderChapterListController: UITableViewController {
         guard let currentItem else { return false }
         return currentItem.href == item.href
     }
-}
+}