fix(utils): re-raise in timed_with_status when no fallback configured

[Ptah-CT]

Fixes #1523.

Problem

timed_with_status caught every exception, ran the optional fallback, but when no fallback was configured the wrapper fell through to an implicit return None. Decorated functions returned None on any failure instead of raising.

Concrete consequence: OpenAILLM.generate (decorated with this) returned None on a MiniMax 400 (chat content is empty (2013) for system-only messages), and the suggestion handler then died in clean_json_response with AttributeError: 'NoneType' object has no attribute 'replace'. The real 400 was hidden.

Change

Add a single raise after the fallback branch:

                if fallback is not None and callable(fallback):
                    result = fallback(e, *args, **kwargs)
                    return result
                # No fallback configured -> re-raise so callers see the failure
                # instead of receiving an implicit None. ...
                raise
            finally:
                ...

finally still runs, so the timing/status log line is unchanged.

Type

• Bug fix (non-breaking change which fixes an issue)

Tested

• Reproduced locally with MOS_CHAT_MODEL=MiniMax-M2.7, OPENAI_API_BASE=https://api.minimax.io/v1, system-only suggestion prompt.
  • Before: HTTP 500 'NoneType' object has no attribute 'replace'
  • After: HTTP 500 surfaces the real openai.BadRequestError: 400 ... invalid params, chat content is empty (2013) to the caller, exactly as [TIMER_WITH_STATUS] already logged.
• Existing fallback path (fallback= arg supplied) is exercised by other handlers; behaviour unchanged because raise is reached only when no fallback returns.

Checklist

• Self-review done
• Comment added explaining the fix
• Unit test added (existing test suite did not cover this branch; happy to add a small one if maintainers want it)
• Linked to issue