Support for CDA view of entities

[cvidmar]

Description

Add a CDA view of entitites, allowing for extraction of published field values and versions and comparison with the CMA version of the entities

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 💥 Breaking change
• 📝 Documentation
• ♻️ Refactoring
• ⚡ Performance
• ✅ Tests
• 🔧 Build/CI

Related Issue

Changes

• Add dual CMA/CDA loading: when a CDA key is provided, published snapshots are fetched and attached to each entity via HasCDAView() / CDAView(), enabling draft-vs-published comparisons without extra API calls
• Add Config.SkipAssets option to skip loading assets entirely, saving time and bandwidth for entry-only migrations
• Add FilterHasCDAView() and FilterNoCDAView() filters
• Add IsFieldNullOrEmpty()
• Add GetReferrerPath()
• Update README and CLAUDE.md with new features

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my own code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.

Notes

Full backward compatibility