feat: add in-reader search and restructure documentation

- Add RDEPUBReaderSearchBarView with animated show/hide, keyword
  navigation, and match counting integrated into the reader controller
- Restructure docs: replace scattered design docs with consolidated
  BUSINESS_LOGIC.md and UML_CLASS_DIAGRAMS.md; update ARCHITECTURE.md
- Add SearchTests and FanrenParseTimeTest; enhance LargeBookOnDemandTests
- Add scripts/run_ui_regression.sh and summarize_ui_results.py for
  automated UI test execution and reporting

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

Sources/RDReaderView/EPUBUI/RDEPUBReaderController+DataSource.swift

@@ -111,6 +111,10 @@ extension RDEPUBReaderController: RDReaderDataSource, RDReaderDelegate {
         readerContext.markUserNavigationActivity()
         updateCurrentSelection(nil)
         reconcileTextPaginationSizeIfNeeded(for: pageNum)
+
+        // 用户开始导航时，应用后台解析完成的完整 map
+        runtime.applyPendingFullPageMapIfNeeded()
+
         if readerContext.bookPageMap != nil {
             _ = runtime.prepareOnDemandChapter(forAbsolutePageNumber: pageNum + 1)
             runtime.extendPartialBookPageMapIfNeeded(currentPageNumber: pageNum + 1)