validate-agent v1.0.0

- Initial release of validate-agent, focusing on agent validation and quality assurance.
- Introduces core principles to minimize silent system errors and provide reproducible evidence.
- Defines clear triggers for validation, including task completion, post-fix, pre-answer, and cross-session commitments.
- Outlines best practices: single-variable changes, enforced post-fix verification, and minimal proactive messaging.
- Includes actionable checklists and key statistics on common agent failure modes.