fix bug encountered when running GLM-4.7-Flash hosted by LM Studio, in
which the provider sends tool call arguments via
`response.function_call_arguments.done` events instead of streaming them
via `response.function_call_arguments.delta` events. The final
`response.output_item.done` event then contains empty `{}` arguments.
The code only handled delta events, so tool calls failed with validation
errors like `"must have required property 'command'"`.
Full disclosure, Opus triaged the bug and provided the fix (by adding
logging statements to the req/resp to the upstream provider (LM
Studio)). I'm to provide prompts/transcripts, and acknowledge that I'm
not an expert in Pi internals at this time.
fb364c89bf