Merge remote-tracking branch 'origin/main'

Fixed error messages to print file with right extension name

Merge remote-tracking branch 'origin/main'

Fixed GitHub Actions workflow not being triggered automatically on pr…

…ogram modification

Fixed typo on automated message being generated upon update

Clarified type of shell for README.md updating commands and also fixe…

…d permissions for GitHub Actions

Fixed issue with 2026 full year calendar. Also updated README.md.