- Add context limit rationale to system_requirements.md with memory formula
- Update SKILL.md to include XReg/covariates in description and usage sections
- Add dataset-aware memory estimation to check_system.py with new CLI args
- Document memory estimation in api_reference.md with Mermaid diagram
- Add dataset preflight section to SKILL.md with examples
Resolves review comments about:
- How context limits (512/1024) were determined
- Including XReg mode description in skill documentation
Bonus enhancement: Dataset preflight checking prevents OOM before loading data.