fix(skill): rewrite senior-ml-engineer with real ML content (#74) (#141)
- Replace 3 boilerplate reference files with real technical content:
- mlops_production_patterns.md: deployment, feature stores, A/B testing
- llm_integration_guide.md: provider abstraction, cost management
- rag_system_architecture.md: vector DBs, chunking, reranking
- Rewrite SKILL.md: add trigger phrases, TOC, numbered workflows
- Remove "world-class" marketing language (appeared 5+ times)
- Standardize terminology to "MLOps" (not "Mlops")
- Add validation checkpoints to all workflows
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>