feat: Add v1.2 features - Exit codes, JSON output, and enhanced badges

[BruinGrowly]

Implemented three major quick wins for v1.2:

1. EXIT CODES FOR CI/CD 🚀

   • Returns meaningful exit codes based on severity: * 0 = All harmonious (excellent or low severity) * 1 = Medium severity found (0.5-0.8) * 2 = High severity found (0.8-1.2) * 3 = Critical severity found (≥ 1.2)
   • Enables automated quality gates in CI/CD pipelines
   • Build fails automatically on high/critical disharmony
   • Perfect for GitHub Actions, GitLab CI, Jenkins, etc.

2. JSON OUTPUT FORMAT 📊

   • New --format json option for machine-readable output
   • Structured data includes:
     • Version and threshold information
     • Per-file function analysis with scores * Severity levels (excellent, low, medium, high, critical) * Summary statistics across all files
   • Enables tool integration (IDEs, dashboards, analytics)
   • Quiet mode automatically enabled for JSON output

3. ENHANCED COMMAND-LINE INTERFACE

   • Added argparse for professional CLI experience
   • New flags:
     • --format {text,json} - Choose output format
     • --threshold FLOAT - Custom disharmony threshold * --version - Show version number * --help - Comprehensive help with examples
   • Improved help text with usage examples
   • Better error messages

4. ENHANCED README BADGES

   • Added CI status badge (links to Actions)
   • Added version badge (links to CHANGELOG)
   • Added test pass rate badge (20 tests passing)
   • Added harmony score badge (meta - tool analyzing itself!)
   • All badges clickable with relevant links

Technical Implementation:

• get_severity() method maps scores to severity levels
• get_highest_severity_code() returns appropriate exit code
• print_json_report() generates structured JSON output
• Quiet mode suppresses text output when using JSON
• All changes backward compatible with existing usage

Documentation Updates:

• CHANGELOG.md: Added v1.2.0 release notes
• QUICK_REFERENCE.md: Added Advanced Options section with:
  • JSON output examples
  • Exit code reference table
  • CI/CD usage examples
• README.md: Enhanced badge section

Testing:

• All 20 existing tests still pass
• Manual testing confirms:
  • Exit codes work correctly (tested with examples/test_code.py → exit 3)
  • JSON output is valid and well-structured
  • Text output unchanged and working
  • --version and --help flags work
• Black formatting applied

Breaking Changes: None

• Existing usage (harmonizer file.py) works unchanged
• Default behavior is text output, exit code 0 for harmonious code
• Fully backward compatible

This release makes Harmonizer production-ready for CI/CD integration and enables tool ecosystem development. 💛⚓