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/ReaderController/RDEPUBReaderChromeCoordinator.swift

@@ -19,12 +19,15 @@ final class RDEPUBReaderChromeCoordinator {
         context.controller
     }
 
-    /// 创建顶部工具栏视图，绑定返回和书签切换回调。
+    /// 创建顶部工具栏视图，绑定返回、搜索和书签切换回调。
     func makeTopToolView() -> RDEPUBReaderTopToolView {
         let toolView = RDEPUBReaderTopToolView()
         toolView.onBack = { [weak self] in
             self?.handleBackAction()
         }
+        toolView.onSearch = { [weak self] in
+            self?.toggleSearchBar()
+        }
         toolView.onToggleBookmark = { [weak self] in
             _ = self?.context.runtime?.toggleBookmark()
         }
@@ -76,6 +79,7 @@ final class RDEPUBReaderChromeCoordinator {
             controller.configuration.allowsHighlights && !controller.activeHighlights.isEmpty
         )
         controller.updateBookmarkChrome()
+        updateSearchBar()
     }
 
     /// 弹出阅读设置面板（字号、字体、行距、分栏、主题、亮度等）。
@@ -140,6 +144,29 @@ final class RDEPUBReaderChromeCoordinator {
         controller.present(navigationController, animated: true)
     }
 
+    /// 切换搜索栏的显示/隐藏状态。
+    func toggleSearchBar() {
+        guard let controller else { return }
+        if controller.isSearchBarVisible {
+            controller.hideSearchBar()
+        } else {
+            controller.showSearchBar()
+        }
+    }
+
+    /// 同步搜索栏的主题和匹配计数。
+    func updateSearchBar() {
+        guard let controller else { return }
+        controller.searchBarView.apply(theme: controller.configuration.theme)
+        if let searchState = controller.searchState {
+            if let index = searchState.currentMatchIndex {
+                controller.searchBarView.updateMatchCount(current: index + 1, total: searchState.matches.count)
+            } else if searchState.matches.isEmpty {
+                controller.searchBarView.showNoResults()
+            }
+        }
+    }
+
     /// 处理返回按钮点击，自动判断 pop 或 dismiss 方式关闭阅读器。
     func handleBackAction() {
         guard let controller else { return }