Security Vulnerabilities and Cross-Platform Issues

[Ananya44444]

1. Insecure DEFAULT SECRET_KEY in Production
   The application allows the hardcoded development SECRET_KEY to be used in production
   This poses a significant security risk as the key is publicly visible in the repository
   No validation exists to ensure SECRET_KEY is properly configured in production environments

2. Cross-Platform Compatibility Issue
   systemctl Command Fails on Non-Linux Systems
   The github_update function attempts to run /bin/systemctl without platform detection
   This causes crashes during development on Windows/macOS systems
   No error handling or graceful fallback for non-Linux environments