feat(delegate_tool): add additional parameters for child agent configuration

Enhanced the _run_single_child function by introducing max_tokens, reasoning_config, and prefill_messages parameters from the parent agent. This allows for more flexible configuration of child agents, improving their operational capabilities.

tools/delegate_tool.py

@@ -205,6 +205,9 @@ def _run_single_child(
             provider=getattr(parent_agent, "provider", None),
             api_mode=getattr(parent_agent, "api_mode", None),
             max_iterations=max_iterations,
+            max_tokens=getattr(parent_agent, "max_tokens", None),
+            reasoning_config=getattr(parent_agent, "reasoning_config", None),
+            prefill_messages=getattr(parent_agent, "prefill_messages", None),
             enabled_toolsets=child_toolsets,
             quiet_mode=True,
             ephemeral_system_prompt=child_prompt,