v0.4.0

Update README for v0.4.0 with comprehensive documentation

- Update all GitHub links to cjhonlyone/zotero-odh
- Add version badge (0.4.0)
- Document new Anki card content display feature
- Document smart word matching (case-insensitive + word forms)
- Add detailed configuration examples
- Add new use cases and workflows
- Update feature status table
- Add 'What's New in v0.4.0' section
- Add troubleshooting for new features
- Update author information to Claude/CJH
- Improve formatting and structure