Agent: Implement sub-agent abstraction layer within agent server

[HyeockJinKim]

Description

Introduce a sub-agent abstraction within the physical agent server to support multiple sub-agent instances with different configurations and scheduling policies.

Requirements

• Define abstract sub-agent interface/base class
• Implement mechanism to instantiate multiple sub-agents within single process
• Support configuration for specifying agent mode (single vs sub-agent)
• Ensure resource isolation between sub-agents (resource allocation, port pools, etc.)
• Design sub-agent identifier scheme

Implementation Details

• Naming: SubAgent
• Each sub-agent should have its own:
  • Sub-agent ID/identifier
  • Resource allocation tracking
  • Port pool management
  • Kernel registry
• Shared components across sub-agents:
  • Docker/container runtime client
  • Physical device access
  • Network interfaces

Backward Compatibility

• Default to single-agent mode for existing deployments
• Single-agent mode should behave identically to current implementation
• Configuration migration path for existing agent configs

Acceptance Criteria

• Agent can be configured in single-agent or sub-agent mode
• Sub-agent mode supports multiple sub-agent instances
• Each sub-agent maintains isolated state
• Existing single-agent configurations work without modification

JIRA Issue: BA-2606