feat: EPUB 阅读器搜索、选中注释、书签 chrome 状态及大量重构优化

- 新增 RDEPUBReaderSearchCoordinator 与 RDEPUBSelectionState 管理搜索和选中状态
- 新增 BookmarkChromeStateTests、NavigationBackwardTests、SelectionAnnotateTests 等 UI 测试
- 新增多个边界测试 epub 样本（损坏结构、空归档、缺失文件、流式外链验证）
- 重构阅读器 chrome 状态管理，统一 tool bar 与 search bar 交互
- 优化大书分页缓存策略（RDEPUBChapterSummaryDiskCache、RDEPUBPageCountCache）
- 移除废弃的 RDEPUBLocationConverter 和 RDEPUBPageBreakPolicy
- 更新 epub-bridge.js 与 JS bridge 通信协议
- 全面更新现有 UI 测试以适配新的 helper 和状态管理

Sources/RDReaderView/EPUBUI/RDURLReaderController.swift

@@ -54,6 +54,9 @@ public final class RDURLReaderController: UIViewController {
     private var demoStateTimer: Timer?
     private var lastEmittedDemoState = ""
     private var pendingSearchKeyword: String?
+    private var externalLinkActivationCount = 0
+    private var lastActivatedExternalURL: URL?
+    private var lastReaderErrorDescription = "none"
 
     /// 初始化方法
     /// - Parameters:
@@ -78,6 +81,7 @@ public final class RDURLReaderController: UIViewController {
         super.viewDidLoad()
         view.backgroundColor = .systemBackground
         title = bookURL.deletingPathExtension().lastPathComponent
+        RDEPUBResourceURLSchemeHandler.resetDebugMetrics()
         embedReaderController()
         installDemoStateLabel()
     }
@@ -370,6 +374,10 @@ public final class RDURLReaderController: UIViewController {
         let progression = location.map { String(format: "%.4f", $0.navigationProgression) } ?? "nil"
         let mapSnapshot = demoPaginationSnapshot()
         let layoutConfig = readerController?.readerContext.currentTextLayoutConfig(pageSize: currentTextPageSize())
+        let resourceMetrics = RDEPUBResourceURLSchemeHandler.debugMetricsSnapshot()
+        let cacheStats = readerController?.readerContext.makeChapterSummaryDiskCache().cacheStatistics
+            ?? (fileCount: 0, totalBytes: 0)
+        let inspectable = readerController?.configuration.allowsInspectableWebViews ?? epubConfiguration.allowsInspectableWebViews
         let state = [
             "reader=opened",
             "page=\(page)",
@@ -389,7 +397,17 @@ public final class RDURLReaderController: UIViewController {
             "avoidOrphans=\(layoutConfig?.avoidOrphans == true ? 1 : 0)",
             "windowSize=\(readerController?.configuration.onDemandChapterWindowSize ?? epubConfiguration.onDemandChapterWindowSize)",
             "parseMs=\(readerController?.readerContext.lastMetadataParseWallClockMs ?? 0)",
-            "parseConcurrency=\(readerController?.readerContext.lastMetadataParseConcurrency ?? 0)"
+            "parseConcurrency=\(readerController?.readerContext.lastMetadataParseConcurrency ?? 0)",
+            "inspectable=\(inspectable ? 1 : 0)",
+            "streamedResources=\(resourceMetrics.streamedResponses)",
+            "inMemoryResources=\(resourceMetrics.inMemoryResponses)",
+            "resourceFailures=\(resourceMetrics.failures)",
+            "cacheFiles=\(cacheStats.fileCount)",
+            "cacheBytes=\(cacheStats.totalBytes)",
+            "externalLinks=\(externalLinkActivationCount)",
+            "lastExternalURL=\(encodedDemoLocationHref(lastActivatedExternalURL?.absoluteString))",
+            "lastError=\(encodedDemoField(lastReaderErrorDescription))",
+            "searchMatchText=\(encodedDemoField(currentSearchMatchText()))"
         ].joined(separator: " ")
         demoStateLabel.text = state
         if let logPrefix {
@@ -405,6 +423,25 @@ public final class RDURLReaderController: UIViewController {
         return href.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? href.replacingOccurrences(of: " ", with: "%20")
     }
 
+    private func encodedDemoField(_ value: String?) -> String {
+        guard let value, !value.isEmpty else { return "nil" }
+        return value.addingPercentEncoding(withAllowedCharacters: .alphanumerics) ?? value.replacingOccurrences(of: " ", with: "_")
+    }
+
+    private func currentSearchMatchText() -> String {
+        guard let match = readerController?.searchState?.currentMatch,
+              let rangeLocation = match.rangeLocation,
+              let chapterData = readerController?.textChapterData(forNormalizedHref: match.href) else {
+            return "none"
+        }
+        let nsRange = NSRange(location: rangeLocation, length: match.rangeLength)
+        guard nsRange.location >= 0,
+              nsRange.location + nsRange.length <= chapterData.attributedContent.length else {
+            return "none"
+        }
+        return chapterData.attributedContent.attributedSubstring(from: nsRange).string
+    }
+
     private func demoPaginationSnapshot() -> (mode: String, phase: String, knownPages: Int, knownChapters: Int, buildableChapters: Int) {
         guard let readerController else {
             return ("unavailable", "none", 0, 0, 0)
@@ -486,6 +523,17 @@ extension RDURLReaderController: RDEPUBReaderDelegate {
     public func epubReader(_ reader: UIViewController, didUpdateBookmarks bookmarks: [RDEPUBBookmark]) {
         emitDemoState(prefix: "bookmarks=\(bookmarks.count)")
     }
+
+    public func epubReader(_ reader: UIViewController, didActivateExternalLink url: URL) {
+        externalLinkActivationCount += 1
+        lastActivatedExternalURL = url
+        emitDemoState(prefix: "externalLinks=\(externalLinkActivationCount)")
+    }
+
+    public func epubReader(_ reader: UIViewController, didFailWithError error: Error) {
+        lastReaderErrorDescription = String(describing: error)
+        emitDemoState(prefix: "lastError=\(lastReaderErrorDescription)")
+    }
 }
 
 /// 翻页模式扩展：提供 Demo 命令行参数值