One-Click Cleanup for Unused Images and Volumes

[guangdawang]

Is your feature request related to a problem? Please describe

Currently, cleaning up unused Docker resources in Portainer requires going to multiple sections:

• Images → manually select unused/dangling images → Remove
• Volumes → manually select unused volumes → Remove
• Containers → filter stopped → Remove

This process is time-consuming and repetitive, especially for developers and testers who frequently build and remove containers. What should be a one-click operation currently takes multiple steps across different pages.

Describe the solution you'd like

Add a one-click "Prune" or "Clean Up Unused" button that does what docker system prune -a does:

• Removes all stopped containers
• Removes all unused volumes
• Removes all dangling images (and optionally all unused images with -a flag)
• Cleans up build cache

UI suggestion:

• Button location: Dashboard, Host overview, or a new "Maintenance" section
• Confirmation dialog showing what will be removed:

  ⬜ Stopped containers (3)
  ⬜ Unused volumes (2)  
  ⬜ Dangling images (12)
  ⬜ Build cache (45 MB)
  [Prune] [Cancel]
  

• Option to include -a (remove all unused images, not just dangling)

Describe alternatives you've considered

• Current manual approach: inefficient for regular cleanup
• SSH into server and run docker system prune -a manually: not ideal for users who prefer GUI management
• Third-party cleanup scripts: extra maintenance overhead

Additional context

This would significantly improve Portainer's usability for daily Docker management, especially on:

• Development environments with frequent builds
• Production servers with limited disk space
• Users managing multiple hosts through Portainer