Increase ask_ai max_rounds default to 5

[zhongkaifu]

Motivation

• ask_ai sometimes returned {'status': 'error', 'results': {'message': 'ask_ai could not produce an answer within the allowed rounds'}} when it exhausted the default iteration budget.
• Increasing the allowed rounds gives the assistant more iterations/calls to produce a structured answer and reduces premature failures.

Description

• Bumped the default max_rounds for ask_ai from 3 to 5 in tools/builtin.py by changing the function signature parameter max_rounds: int = 3 to max_rounds: int = 5.
• No other behavior or control flow around the retry loop was modified; only the default iteration budget was increased.

Testing

• No automated tests were run for this change.
• The code change is limited to a single default parameter update and does not alter test harnesses or CI settings.
• Local code inspection (rg/sed) was used to locate and modify the ask_ai implementation prior to the change.
• Recommend running existing unit/integration tests and exercising ask_ai flows to validate the new default in environments that previously hit the round limit.

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Codex Task