Add comprehensive Docker container management with agent-centric organization:
Backend enhancements:
- Add DockerPort struct for container port mappings
- Extend DockerContainer model with agent hostname and ports
- Enhance Docker handlers to fetch agent information
- Extract port data from container metadata
- Support both container and host port display
Frontend improvements:
- Group containers by agent with clear visual separation
- Display agent hostnames instead of UUIDs
- Add dedicated Ports column with formatted mappings
- Show container counts and update status per agent
- Improve version delta display with visual indicators
This provides a much more intuitive interface for managing
Docker containers across multiple agents while maintaining
compatibility with existing approval workflows.