Summary

Infinite Rebuild Loop when a Markdown file exists but is not listed in SUMMARY.md.

When a .md file (e.g., app.md) exists in the project directory but is not explicitly defined in SUMMARY.md, HonKit's watch mode (via honkit serve) enters an infinite loop of rebuilding.

• HonKit version: (Please fill your version, e.g., 6.0.0)
  "honkit": "^6.1.4"

Step to reproduce

1. Create a HonKit project.
2. Add a Markdown file (e.g., app.md) to the directory.
3. Keep SUMMARY.md without any reference to app.md.
4. Run honkit serve.
5. Observe the console output.

• Link to code example: (Optional: Put your repo link here)

Actual results

The console shows a continuous loop of rebuilding the same file every 0.1s:

info: >> generation finished with success in 0.0s ! 
warn: >> Rebuild /usr/local/var/www/uploads/app.md 
info: >> generation finished with success in 0.0s ! 
warn: >> Rebuild /usr/local/var/www/uploads/app.md 
info: >> generation finished with success in 0.0s !