Research macOS Native Container Runtime Integration

## Objective

Research and evaluate macOS native container runtime options for Backend.AI Agent integration.

## Scope

- Investigate available container runtimes (Lima, Colima, OrbStack, etc.)
- Analyze integration feasibility with current Agent architecture
- Document API compatibility and performance characteristics
- Identify potential blockers and limitations

## Deliverables

- Research document with findings and recommendations
- Compatibility matrix for different runtime options
- Proposed integration approach

JIRA Issue: BA-4043