* Partial amendment
* Update install-agent.sh
* Update install-agent.sh
Fix if is_alpine function with user creation and permission issues
* Update install-agent.sh
Adding an Uninstallation Process to Alpine
Using deluser instead of userdel in Alpine
- Add `-c` flag to use GitHub mirror (ghp.ci) for mainland China users
- Implement checksum verification for downloaded files
- Add progress bar for file downloads
This change improves installation reliability and user experience,
especially for users in regions (China mainland etc.) with limited GitHub access.