- Add CHANGELOG.md, CODE_OF_CONDUCT.md, and Contribute.md for documentation and community standards
- Add tools/add_spdx_header.sh for SPDX license header management
- Refactor BookmarksView and BookmarksViewModel to support dependency injection via UseCaseFactory
- Add retroactive extension for String: Identifiable in StringExtension.swift
- Update MockUseCaseFactory and MockGetBookmarksUseCase to provide mock data for previews and tests
- Update README.md: add TestFlight info, changelog link, HTTPS/local network note, and move planned features to changelog
- Add protocols for all UseCases and implement them in their respective classes
- Add DefaultUseCaseFactory and MockUseCaseFactory for dependency injection
- Implement all mock UseCases with dummy data
- Start migration of view models and views to protocol-based UseCase injection (not all migrated yet)
- Refactor previews and some initializers for easier testing
- Move SectionHeader to Components, update server settings UI text
- Add sample article.html for mock content
