Allow subagent nodes to transition immediately after tool calls

Feature Requests
1

It would be useful if subagent nodes could evaluate transition conditions immediately after a tool/function call completes.

Example:

  1. A subagent collects one missing field from the caller.
  2. It calls a tool to validate or classify the answer.
  3. The tool returns something like next_step = "schedule" or next_step = "transfer".
  4. The parent flow should be able to transition right away based on that returned value.

Right now, it seems like the subagent often needs another conversation turn before transitions are evaluated. That can create awkward filler responses or require extra loop nodes just to move the flow forward.

A node/tool option like evaluate_transitions_after_tool_call: true would make subagents much better for structured workflows where a tool result determines the next node.