Add chapters, history, bookmarks, live download progress, and i18n

- Chapter navigation with auto-scroll to current chapter and end-of-chapter sleep timer
- Opt-in listening history (local-only) with XML export and per-item quick menu
- Bookmarks with server sync via Audiobookshelf API
- Live MB counter during downloads via URLSessionDownloadTask delegate
- In-progress downloads shown in "Heruntergeladen" with dimmed cover + ring overlay
- Cover image cache (50 MB memory / 500 MB disk URLCache)
- German/English localization (de.lproj, en.lproj)
- Loading spinner now triggers immediately on view switch instead of waiting for the network

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ABS Client/Audiobookshelf swift/Views/LibraryListView.swift

@@ -12,13 +12,14 @@ enum LibraryLayout: String, CaseIterable, Identifiable {
 struct LibraryListView: View {
     let items: [LibraryItem]
     var onRefresh: (() async -> Void)? = nil
+    var dimDownloading: Bool = false
     let onSelect: (LibraryItem) -> Void
 
     var body: some View {
         #if os(iOS)
         List {
             ForEach(items) { item in
-                LibraryListRow(item: item)
+                LibraryListRow(item: item, dimDownloading: dimDownloading)
                     .contentShape(Rectangle())
                     .onTapGesture { onSelect(item) }
                     .listRowInsets(EdgeInsets(top: 8, leading: 16, bottom: 8, trailing: 16))
@@ -32,7 +33,7 @@ struct LibraryListView: View {
         ScrollView {
             LazyVStack(spacing: 0) {
                 ForEach(Array(items.enumerated()), id: \.element.id) { idx, item in
-                    LibraryListRow(item: item)
+                    LibraryListRow(item: item, dimDownloading: dimDownloading)
                         .contentShape(Rectangle())
                         .onTapGesture { onSelect(item) }
                     if idx < items.count - 1 {
@@ -49,10 +50,17 @@ struct LibraryListView: View {
 struct LibraryListRow: View {
     @Environment(AppState.self) private var app
     let item: LibraryItem
+    var dimDownloading: Bool = false
 
     var body: some View {
         HStack(spacing: 12) {
-            cover
+            ZStack {
+                cover
+                    .opacity(dimDownloading && isActivelyDownloading ? 0.55 : 1.0)
+                if dimDownloading, case .downloading(let p) = app.downloads.state(for: item.downloadKey) {
+                    LargeDownloadOverlay(progress: p, size: 40)
+                }
+            }
             VStack(alignment: .leading, spacing: 2) {
                 Text(item.title)
                     .font(.headline)
@@ -77,18 +85,27 @@ struct LibraryListRow: View {
                     #endif
                 }
             }
+            .opacity(dimDownloading && isActivelyDownloading ? 0.55 : 1.0)
             Spacer(minLength: 8)
             #if os(macOS)
-            if item.durationSeconds > 0 {
+            if dimDownloading, app.downloads.downloadedBytes(for: item.downloadKey) > 0 {
+                Text(formatBytes(app.downloads.downloadedBytes(for: item.downloadKey)))
+                    .font(.caption.monospacedDigit())
+                    .foregroundStyle(.secondary)
+                    .opacity(dimDownloading && isActivelyDownloading ? 0.55 : 1.0)
+            } else if item.durationSeconds > 0 {
                 Text(formatDuration(item.durationSeconds))
                     .font(.caption.monospacedDigit())
                     .foregroundStyle(.secondary)
+                    .opacity(dimDownloading && isActivelyDownloading ? 0.55 : 1.0)
             }
             #endif
-            downloadStatus
-                #if os(macOS)
-                .frame(width: 28)
-                #endif
+            if !(dimDownloading && isActivelyDownloading) {
+                downloadStatus
+                    #if os(macOS)
+                    .frame(width: 28)
+                    #endif
+            }
         }
         #if os(macOS)
         .padding(.horizontal, 16)
@@ -97,6 +114,11 @@ struct LibraryListRow: View {
         .contextMenu { downloadMenuItems }
     }
 
+    private var isActivelyDownloading: Bool {
+        if case .downloading = app.downloads.state(for: item.downloadKey) { return true }
+        return false
+    }
+
     private var cover: some View {
         Group {
             if let url = app.client.coverURL(itemId: item.id) {