chore: fix description trap, add When to Use section

[CybotTM]

Quality Review Finding

Per marketplace tracking issue:

Word count: 800

Issues

1. Description trap — description summarizes the workflow instead of listing trigger conditions
2. No "When to Use" section — has "Expertise Areas" and "Explicit Content Triggers" but no formal section
3. Quick Reference before Overview — structure should be: Frontmatter → Overview → When to Use → Quick References
4. Narrative structure dominates — "Explicit Content Triggers" is wordy

Recommended Actions

• Rewrite description: "Use when establishing git branching strategies, implementing conventional commits, managing pull requests, merging code with signed commits, or resolving merge conflicts."
• Add formal "## When to Use" section at top
• Consolidate "Expertise Areas" and "Explicit Content Triggers" into one "When to Use" section
• Move Quick Reference sections after Overview + When to Use