This PR significantly improves the quality of AI-generated commit messages by replacing simplistic prompts with rich, intention-revealing instructions and adding robust output quality controls.

Key Improvements

🎯 Rich, Context-Aware Prompts

Replaced basic prompts with comprehensive instructions that:

• Emphasize inferring the underlying intent/WHY of changes rather than mechanical file listings
• Enforce imperative mood and encourage specific action verbs (Add, Fix, Refactor, Optimize) over bland terms like "update"
• Provide tailored guidance for different scenarios:
  • Static assets only → "Refine layout spacing", "Update hero images"
  • Tests only → "Add tests for X feature"
  • Performance changes → "Optimize query building"
  • Error handling → "Handle nil pointer in config loader"

🔄 Two Distinct Prompt Templates

• File-list mode (..): Derives intent purely from changed file names and static/non-static separation
• Diff mode (.): Analyzes full diff content plus static file list for deeper context

📏 Enhanced Output Quality

• Increased token limit: 20 → 40 tokens to allow more nuanced single-line titles
• Post-processing controls:
  • Ensures single line only (strips content after first newline)
  • Enforces ≤70 character limit with smart truncation
  • Removes quotes, punctuation, and code fences

Example Output Improvements

Before:

Update main.go and styles.css

After:

Add user authentication with responsive login form

Backward Compatibility

✅ All existing functionality preserved:

• Only processes commit messages "." and ".."
• Maintains debug logging to .git/commit-msg-debug.log
• Continues excluding static assets from diffs
• No new external dependencies

The implementation compiles cleanly and maintains the same CLI interface while dramatically improving commit message quality through better AI instruction and output sanitization.

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