- Replace callback-based architecture with Feature Registration Pattern
- Add feature registry for modular feature initialization
- Create createNavigationAPI() for unified page/chapter navigation
- Implement renderCurrentPage() for PDF/comic/manga rendering
- Add updateProgress() to sync reading progress to backend
- Support ebook, PDF, comic, and manga readers in single interface
- Remove 600+ lines of callback wiring code
- reader-shell now acts as lightweight orchestrator
- Delegates specific functionality to feature modules
- Parse ebooks using parser-manager with format routing
- Initialize readers based on library type from metadata