refactor: rename RDReaderView -> RDEpubReaderView, update pod config and docs

- Rename source module from RDReaderView to RDEpubReaderView
- Move all source files from Sources/RDReaderView/ to Sources/RDEpubReaderView/
- Update podspec: RDReaderView.podspec -> RDEpubReaderView.podspec
- Update Podfile, demo project, and CocoaPods config for new pod name
- Delete old RDReaderView pod support files from ReadViewDemo/Pods
- Add new RDEpubReaderView pod support files
- Update documentation (API ref, architecture, UML, conventions, etc.)
- Add FixedLayoutRotationTests
- Update .gitignore: exclude .DS_Store, manual unpack backups, _ssoft-output

Sources/RDEpubReaderView/ReaderView/RDEpubReaderView+ContentAccess.swift

@@ -0,0 +1,68 @@
+
+import UIKit
+
+extension RDEpubReaderView {
+
+    public func register(contentView: UIView.Type, contentViewWithReuseIdentifier identifier: String) {
+        contentViews[identifier] = contentView
+        collectionView.register(RDEpubReaderContentCell.self, forCellWithReuseIdentifier: identifier)
+    }
+
+    public func dequeueReusableContentView(withReuseIdentifier identifier: String, for pageNum: Int) -> UIView {
+        if self.currentDisplayType != .pageCurl, let cell = self.collectionView.cellForItem(at: IndexPath(row: pageNum, section: 0)) as? RDEpubReaderContentCell, let containerView = cell.containerView {
+            return containerView
+        }
+        let contentViewClass = contentViews[identifier]
+        assert(contentViewClass != nil, "请调用register(contentView：contentViewWithReuseIdentifier：）")
+        let contentView = contentViewClass!.init()
+        return contentView
+    }
+
+    public func pageContentView(pageNum: Int) -> UIView? {
+        if currentDisplayType == .pageCurl {
+            return (self.pageViewController.viewControllers?.first as? RDEpubReaderPageChildViewController)?.contentView
+        } else {
+            let cell = collectionView.cellForItem(at: IndexPath(item: pageNum, section: 0)) as? RDEpubReaderContentCell
+            return cell?.containerView
+        }
+    }
+
+    public func resolvedSinglePageSize(pageNum: Int? = nil) -> CGSize {
+        let targetPage = pageNum ?? (currentPage >= 0 ? currentPage : nil)
+        if let targetPage,
+           let contentView = pageContentView(pageNum: targetPage),
+           contentView.bounds.width > 0,
+           contentView.bounds.height > 0 {
+            return contentView.bounds.size
+        }
+
+        if currentDisplayType == .pageCurl {
+            if let childViewController = pageViewController.viewControllers?.first as? RDEpubReaderPageChildViewController,
+               childViewController.view.bounds.width > 0,
+               childViewController.view.bounds.height > 0 {
+                return childViewController.view.bounds.size
+            }
+            if pageViewController.view.bounds.width > 0, pageViewController.view.bounds.height > 0 {
+                return pageViewController.view.bounds.size
+            }
+            return bounds.size
+        }
+
+        let containerBounds = collectionView.bounds.size == .zero ? bounds.size : collectionView.bounds.size
+        guard containerBounds.width > 0, containerBounds.height > 0 else {
+            return bounds.size
+        }
+
+        switch currentDisplayType {
+        case .horizontalScroll:
+            return CGSize(
+                width: containerBounds.width / CGFloat(max(pagesPerScreen, 1)),
+                height: containerBounds.height
+            )
+        case .verticalScroll:
+            return containerBounds
+        case .pageCurl:
+            return bounds.size
+        }
+    }
+}