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/RDURLReaderController.swift

@@ -146,6 +146,19 @@ public final class RDURLReaderController: UIViewController {
         }
     }
 
+    /// 执行搜索（Demo 用）
+    /// 显示搜索栏并提交关键词
+    /// - Parameter keyword: 搜索关键词
+    public func performDemoSearch(keyword: String) {
+        guard let readerController else { return }
+        readerController.showSearchBar()
+        // 等搜索栏动画完成后提交搜索
+        DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
+            readerController.search(keyword: keyword)
+            readerController.updateSearchCount()
+        }
+    }
+
     /// 嵌入阅读器控制器到当前视图层级
     /// 根据文件类型选择合适的阅读器控制器，并通过 Child View Controller 方式嵌入
     private func embedReaderController() {