优化 EPUB 翻页与后台分页刷新

Sources/RDReaderView/EPUBUI/ReaderController/RDEPUBReaderPaginationCoordinator.swift

@@ -191,12 +191,21 @@ final class RDEPUBReaderPaginationCoordinator {
                     runtime: runtime,
                     layoutSnapshot: layoutSnapshot
                 )
+                RDEPUBBackgroundTrace.log(
+                    "Pagination",
+                    "anchorChapterReady spine=\(runtimeChapter.spineIndex) pages=\(runtimeChapter.pages.count)"
+                )
                 let initialChapters = self.loadInitialInteractiveRuntimeChapters(
                     anchorChapter: runtimeChapter,
                     publication: publication,
                     runtime: runtime,
                     layoutSnapshot: layoutSnapshot
                 )
+                let initialPageCount = initialChapters.reduce(0) { $0 + $1.pages.count }
+                RDEPUBBackgroundTrace.log(
+                    "Pagination",
+                    "initialInteractiveChapters ready count=\(initialChapters.count) pages=\(initialPageCount) spines=\(initialChapters.map(\.spineIndex))"
+                )
 
                 DispatchQueue.main.async {
                     guard context.paginationToken == token,
@@ -220,9 +229,17 @@ final class RDEPUBReaderPaginationCoordinator {
                         parser: parser,
                         publication: publication
                     )
+                    RDEPUBBackgroundTrace.log(
+                        "Pagination",
+                        "startingMetadataWorker token=\(token.uuidString) anchorSpine=\(runtimeChapter.spineIndex) partialPages=\(partialMap.totalPages) partialChapters=\(partialMap.totalChapters)"
+                    )
                     worker.start(token: token, restoreLocation: restoreLocation)
                 }
             } catch {
+                RDEPUBBackgroundTrace.log(
+                    "Pagination",
+                    "initialPaginationFailed error=\(String(describing: error)) prioritizedCandidates=\(prioritizedCandidates)"
+                )
                 DispatchQueue.main.async {
                     guard context.paginationToken == token,
                           context.controller != nil else { return }