Integrates webmail and emailDelivery apps, mail-server and install/upgrade
paths, cyberpanel_ols 2.7.0-style binaries, and v2.4.5 UI patterns while
preserving v2.5.5-dev behavior (SnappyMail/PUBLIC_ROOT, childPath in
launchChild, hardened downloads and SSH activity modal).
- Updated .gitignore to include additional sensitive files and directories.
- Added python-dotenv to requirements for loading environment variables.
- Modified settings.py to load environment variables for sensitive configurations, including SECRET_KEY, DEBUG, and database credentials.
- Implemented secure .env file generation during installation to avoid hardcoding sensitive information.
- Introduced fallback method for settings update if environment generation fails.