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/RDEPUBReaderContext.swift

@@ -50,6 +50,9 @@ final class RDEPUBReaderContext {
     var paginator: RDEPUBPaginator?
     /// 全文搜索状态。
     var searchState: RDEPUBSearchState?
+    /// 后台解析完成的完整 BookPageMap，等待用户下次导航时应用。
+    /// 避免后台解析完成时直接替换 map 导致当前阅读位置跳转。
+    var pendingFullPageMap: RDEPUBBookPageMap?
     /// 上次文本分页时的页面尺寸，用于检测是否需要重新分页。
     var lastTextPaginationPageSize: CGSize?
     /// 后台元数据解析耗时（毫秒），仅包含 OperationQueue 并行阶段。
@@ -205,18 +208,6 @@ final class RDEPUBReaderContext {
     }
 
     func chapterCacheKey(forSpineIndex spineIndex: Int) -> RDEPUBChapterCacheKey {
-        let style = currentTextRenderStyle()
-        let pageSize = currentTextPageSize()
-        let layoutConfig = currentTextLayoutConfig(pageSize: pageSize)
-        let renderSignature = [
-            style.font.fontName,
-            "\(style.font.pointSize)",
-            "\(configuration.lineHeightMultiple)",
-            "\(style.lineSpacing)",
-            layoutConfig.cacheSignature,
-            "\(RDEPUBChapterSummary.currentSchemaVersion)"
-        ].joined(separator: "|")
-
         let contentHash: String
         if let parser,
            let publication,
@@ -226,15 +217,53 @@ final class RDEPUBReaderContext {
         } else {
             contentHash = ""
         }
+        return chapterCacheKey(
+            forSpineIndex: spineIndex,
+            precomputedContentHash: contentHash,
+            renderSignature: currentRenderSignature()
+        )
+    }
 
-        return RDEPUBChapterCacheKey(
+    /// 使用预计算的 contentHash 构建缓存键，避免重复读取 HTML 和计算 SHA-256。
+    /// 后台批量解析必须走此版本。
+    func chapterCacheKey(forSpineIndex spineIndex: Int, precomputedContentHash: String) -> RDEPUBChapterCacheKey {
+        chapterCacheKey(
+            forSpineIndex: spineIndex,
+            precomputedContentHash: precomputedContentHash,
+            renderSignature: currentRenderSignature()
+        )
+    }
+
+    /// 使用固定的渲染签名与预计算 contentHash 构建缓存键。
+    /// 适合后台任务在启动时冻结分页参数后复用，避免 live context 漂移。
+    func chapterCacheKey(
+        forSpineIndex spineIndex: Int,
+        precomputedContentHash: String,
+        renderSignature: String
+    ) -> RDEPUBChapterCacheKey {
+        RDEPUBChapterCacheKey(
             bookID: currentBookIdentifier ?? "",
             spineIndex: spineIndex,
             renderSignature: renderSignature,
-            chapterContentHash: contentHash
+            chapterContentHash: precomputedContentHash
         )
     }
 
+    /// 当前渲染参数签名，所有章节共享同一值。
+    func currentRenderSignature() -> String {
+        let style = currentTextRenderStyle()
+        let pageSize = currentTextPageSize()
+        let layoutConfig = currentTextLayoutConfig(pageSize: pageSize)
+        return [
+            style.font.fontName,
+            "\(style.font.pointSize)",
+            "\(configuration.lineHeightMultiple)",
+            "\(style.lineSpacing)",
+            layoutConfig.cacheSignature,
+            "\(RDEPUBChapterSummary.currentSchemaVersion)"
+        ].joined(separator: "|")
+    }
+
     func chapterSummary(forSpineIndex spineIndex: Int) -> RDEPUBChapterSummary? {
         runtime?.summaryDiskCache.read(for: chapterCacheKey(forSpineIndex: spineIndex))
     }