feat(reader): add ebook reader features

- Update copy-handler.ts: export enableContextMenuCopy for text selection
- Update typography-engine.ts: export applyTypography and getFontStack
- Update view-modes.ts: export setViewMode and getCurrentViewMode
- Enable text copying with citation for ebooks
- Add typography engine with font loading and text formatting
- Add view mode support (paginated, scrolled, single/dual column)
- These features integrate with settings-manager for customization

web/src/reader/ebook/view-modes.ts

@@ -2,11 +2,6 @@
 
 type ViewMode = "paginated" | "scrolled" | "single-column" | "double-column";
 
-// Different viewing modes for ebooks
-// Procedural implementation (no OOP)
-
-type ViewMode = "paginated" | "scrolled" | "single-column" | "double-column";
-
 interface ViewModeState {
   currentMode: ViewMode;
   currentPage: number;
@@ -156,3 +151,5 @@ function getTotalPageCount(container: HTMLElement): number {
 
   return Math.ceil(totalHeight / pageHeight);
 }
+
+export { setViewMode, getCurrentViewMode };