Description

After #1434 (DagScheduler wiring), /plan confirm executes the plan but immediately fails with "no agent available for task" because AgentRouter cannot find any agent to handle tasks.

Reproduction

[orchestration]
enabled = true

/plan goal Write a hello world in Rust
/plan confirm

Output:

Confirmed. Executing plan (3 tasks)...
WARN no agent available for task task_id=0 title=Create a new Rust project
Plan failed. 1/3 tasks failed:
  - Create a new Rust project: unknown error

Expected

When no sub-agents are configured (count=0), the AgentRouter's 3-step fallback should use the main agent to execute tasks inline.

Additional issue

After plan failure, /plan status still reports "A plan is awaiting confirmation" instead of the actual "failed (retryable)" state. /plan list correctly shows "failed (retryable)".

Severity

Medium — DagScheduler is now wired (#1434) but unusable without sub-agents or main-agent fallback.