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/EPUBUI/ReaderController/ChapterRuntime/RDEPUBPageResolver.swift

@@ -0,0 +1,40 @@
+import Foundation
+
+struct RDEPUBResolvedPage {
+
+    let page: RDEPUBTextPage
+
+    let chapter: RDEPUBRuntimeChapter
+
+    let chapterIndex: Int
+}
+
+final class RDEPUBPageResolver {
+
+    private unowned let context: RDEPUBReaderContext
+
+    private let store: RDEPUBChapterRuntimeStore
+
+    init(context: RDEPUBReaderContext, store: RDEPUBChapterRuntimeStore) {
+        self.context = context
+        self.store = store
+    }
+
+    func resolvePage(absolutePageIndex: Int) -> RDEPUBResolvedPage? {
+        guard let bookPageMap = context.bookPageMap,
+              let spineIndex = bookPageMap.spineIndex(forAbsolutePage: absolutePageIndex),
+              let localPageIndex = bookPageMap.localPageIndex(forAbsolutePage: absolutePageIndex),
+              let chapter = store.chapterData(for: spineIndex),
+              chapter.pages.indices.contains(localPageIndex),
+              let chapterIndex = bookPageMap.chapterIndex(forSpineIndex: spineIndex) else {
+            return nil
+        }
+
+        var page = chapter.pages[localPageIndex]
+        page.absolutePageIndex = absolutePageIndex
+        page.chapterIndex = chapterIndex
+        page.pageIndexInChapter = localPageIndex
+        page.totalPagesInChapter = chapter.pages.count
+        return RDEPUBResolvedPage(page: page, chapter: chapter, chapterIndex: chapterIndex)
+    }
+}