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/RDEPUBChapterDataCache.swift

@@ -0,0 +1,75 @@
+import Foundation
+
+final class RDEPUBChapterDataCache {
+
+    private var storage: [Int: RDEPUBRuntimeChapter] = [:]
+    private var accessOrder: [Int] = []  // H-05: LRU tracking for eviction
+    private let maxEntryCount: Int
+
+    private let lock = NSLock()
+
+    init(maxEntryCount: Int = 30) {
+        self.maxEntryCount = maxEntryCount
+    }
+
+    subscript(_ spineIndex: Int) -> RDEPUBRuntimeChapter? {
+        get {
+            lock.lock()
+            defer { lock.unlock() }
+            guard let chapter = storage[spineIndex] else {
+                return nil
+            }
+            touchLocked(spineIndex)
+            return chapter
+        }
+        set {
+            lock.lock()
+            defer { lock.unlock() }
+            if let newValue {
+                storage[spineIndex] = newValue
+                touchLocked(spineIndex)
+                // Evict oldest entries if over limit
+                evictIfNeededLocked()
+            } else {
+                storage.removeValue(forKey: spineIndex)
+                accessOrder.removeAll { $0 == spineIndex }
+            }
+        }
+    }
+
+    var storedSpineIndices: [Int] {
+        lock.lock()
+        defer { lock.unlock() }
+        return Array(storage.keys)
+    }
+
+    func remove(spineIndex: Int) {
+        lock.lock()
+        defer { lock.unlock() }
+        storage.removeValue(forKey: spineIndex)
+        accessOrder.removeAll { $0 == spineIndex }
+    }
+
+    func removeAll() {
+        lock.lock()
+        defer { lock.unlock() }
+        storage.removeAll()
+        accessOrder.removeAll()
+    }
+
+    /// H-05: Evict least recently used entries when cache exceeds maxEntryCount.
+    /// Must be called while holding lock.
+    private func evictIfNeededLocked() {
+        while storage.count > maxEntryCount, let oldest = accessOrder.first {
+            storage.removeValue(forKey: oldest)
+            accessOrder.removeFirst()
+        }
+    }
+
+    /// Marks an entry as most recently used.
+    /// Must be called while holding lock.
+    private func touchLocked(_ spineIndex: Int) {
+        accessOrder.removeAll { $0 == spineIndex }
+        accessOrder.append(spineIndex)
+    }
+}