docs: Add 100% MVAA milestone blog post

Epic blog post documenting the journey from 14% to 59% autonomy:
- 8 phases of implementation
- 21 commits, 2,788 LOC
- Complete GitHub issue → PR workflow
- Multi-language test execution
- LLM-powered error recovery
- CI failure handling
- PR review iteration

Includes technical deep dives, lessons learned, and honest limitations.
References permanent capabilities.md doc instead of temporary gap analysis.

Author: jadercorrea