Hermes-agent adds async task delegation for background subagents

Hermes-agent now supports delegate_task(background=true) to run subagents asynchronously. The main session continues uninterrupted while results return as a new turn.

Developers can now use delegatetask with background set to true in hermes-agent to run subagents for long research or build tasks. Vibe builders and basic users keep their main session active while the subagent works separately. Results return automatically as a new turn.