Module subtask 

Subtask abstraction — async spawn/join integrated with ThreadManager.

This module provides the unified mechanism for running concurrent work:

• Subagents spawned by the main agent (joinable, return a result)
• Background tasks (long-running, may not return)
• One-shot tasks (quick async work that returns a result)

All subtasks:

• Run as tokio tasks
• Create a thread entry in ThreadManager on spawn
• Update thread status on completion/failure
• Support cancellation via CancellationToken
• Support agent-settable descriptions (shown in sidebar)

Structs

SpawnOptions

Options for spawning a subtask.

SubtaskHandle

Handle to a running subtask. Allows joining, cancelling, and updating status.

SubtaskRegistry

Registry of active subtask handles for a session.

Enums

SubtaskResult

Result of a completed subtask.

Functions

spawn_background

Spawn a long-running background thread.

spawn_subagent

Spawn a subagent as an async subtask.

spawn_task

Spawn a one-shot background task.