docs: add AGENTS.md to track project changes

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Summary

This PR adds AGENTS.md to document significant changes and implements automated changelog updates via GitHub Actions.

Changes

Documentation

• Created AGENTS.md with comprehensive project documentation
• Documented initial project setup from October 2025
• Detailed architecture overview (scanner, generator, CLI, templates)
• Listed all core features and capabilities
• Outlined development workflow and extension points
• Included roadmap for planned enhancements

Automation

• Created GitHub Action (.github/workflows/update-agents.yml) to auto-update AGENTS.md
• Implemented Node.js script (.github/scripts/update-agents.mjs) that:
  • Parses commit messages using Conventional Commits format
  • Filters significant commits (feat, fix, refactor, perf, breaking)
  • Extracts key changes from commit body and files
  • Organizes entries by month with commit hash and date
  • Updates AGENTS.md and commits changes automatically
• Added documentation for automation scripts

How the automation works

1. Triggers on every push to main branch
2. Analyzes commit type and changed files
3. Skips non-significant commits (chore, style, etc.)
4. Extracts changes from commit body or infers from files
5. Adds formatted entry to current month section in AGENTS.md
6. Updates timestamp and commits back to repository

Benefits

• Automatic tracking of all significant changes
• Historical context for project evolution
• Reduced manual work maintaining changelog
• Consistent formatting across all entries
• Better contributor visibility into project changes

Testing

Tested locally with:

node .github/scripts/update-agents.mjs <commit-hash>

The script correctly:

• Identifies significant vs non-significant commits
• Parses conventional commit formats
• Extracts changes from body and files
• Updates AGENTS.md with proper formatting
• Skips self-referential updates

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This agent session was co-authored by frpboy12 and Continue.