fix(subagents): raise general-purpose max_turns to 150 and default timeout to 30min (#3610)

* fix(subagents): raise general-purpose max_turns to 150 and default timeout to 30min

Deep-research subtasks failed out of the box with GraphRecursionError (Recursion limit of 100 reached): the built-in general-purpose subagent caps at max_turns=100. Raise it to 150 and bump the default subagent timeout from 900s (15min) to 1800s (30min) so the extra turns have time to run instead of shifting the failure to a timeout. The lead agent recursion_limit (100) is unchanged; the failures are subagent-only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* docs(subagents): clarify lead recursion_limit is independent of subagent max_turns

Add comments at both lead recursion_limit=100 sites (gateway services + channel manager) explaining the lead's LangGraph super-step budget is separate from subagent depth, so the two 100s are not conflated. Comment-only, no behavior change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* docs(subagents): clarify built-in vs custom timeout scope; pin bash max_turns in test

Review follow-ups: (1) clarify SubagentConfig docstring + global timeout field/comment that the 1800 default applies to built-in subagents (custom agents keep their own timeout_seconds); (2) pin bash.max_turns==60 in the defaults regression test so the config.example.yaml doc cannot drift; (3) rename test_default_timeout_preserved_when_no_config -> test_explicit_global_timeout_propagates_to_general_purpose since it intentionally exercises an explicit non-default 900. No runtime behavior change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

backend/packages/harness/deerflow/subagents/builtins/general_purpose.py

@@ -57,5 +57,5 @@ You have access to the same sandbox environment as the parent agent:
     tools=None,  # Inherit all tools from parent
     disallowed_tools=["task", "ask_clarification", "present_files"],  # Prevent nesting and clarification
     model="inherit",
-    max_turns=100,
+    max_turns=150,
 )