Fix agent loading and categorization issues

- Fixed YAML frontmatter errors in all agent files causing loading failures
- Added proper category fields to all 16 agents for correct classification
- Standardized agent names to match filenames for consistency
- Updated TODO.md to reflect completed agent system fixes
- Enhanced agents-install-cli make target with pip upgrade and user guidance

All agents now load properly without warnings and display in correct categories:
- Documentation (1), Code Quality (4), Project Management (4)
- Development Process (3), Infrastructure (1), Testing (3)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

agents/agent-code-refactoring.md

@@ -1,7 +1,8 @@
 ---
-name: refactoring-assistant
+name: code-refactoring
 description: Analyze code structure and quality, identify improvement opportunities, and provide actionable refactoring guidance. Use PROACTIVELY for code quality assessment and improvement.
 model: inherit
+category: code-quality
 ---
 
 # Refactoring Assistant - Code Structure and Quality Improvement Agent