[TASK] Phase 2: Skill Enhancement - Categorization and Issue Management

Description

Enhance the cicd-diagnostics skill with comprehensive categorization logic and issue management capabilities:

• Implement failure categorization (flaky tests, deterministic, merge conflicts, workflow issues, PR out of date)
• Add issue management with interactive/automated modes
• Create detection patterns for all failure types
• Update skill documentation

This is Phase 2 of the Auto-Remediation EPIC (#34656).

Acceptance Criteria

• .claude/skills/cicd-diagnostics/utils/categorization.py created with all category detection logic
• .claude/skills/cicd-diagnostics/utils/issue_management.py created with interactive/automated modes
• Detection patterns added to REFERENCE.md (merge conflicts, PR out of date, workflow issues, timing patterns)
• SKILL.md updated with comprehensive categorization guidance
• Test locally: skill correctly categorizes known failure types
• Interactive mode prompts user before creating issues
• Automated mode (CI) creates issues without prompting
• Duplicate detection works (checks if run already analyzed)

Priority

High

Additional Context

Files to Create:

• .claude/skills/cicd-diagnostics/utils/categorization.py
• .claude/skills/cicd-diagnostics/utils/issue_management.py

Files to Modify:

• .claude/skills/cicd-diagnostics/SKILL.md
• .claude/skills/cicd-diagnostics/REFERENCE.md
• .claude/skills/cicd-diagnostics/requirements.txt (add PyGithub)

Depends on: Phase 1 (#34657)

Related: Parent EPIC #34656

Start by reviewing Phase 1 (#34657), then inspect .claude/skills/cicd-diagnostics/SKILL.md, REFERENCE.md, and requirements.txt. Implement the two specified utility modules, update the documentation and dependency, and verify the listed categorization, interactive/automated issue creation, and duplicate-detection acceptance criteria locally.