feat: Add handling for openai full tool call in a single stream chunk (WIP)

[noahlwest]

I was experimenting with Z.ai's GLM 4.6 model served with openai-compatible endpoint from vllm, and noticed that it gives output in a slightly different format from other models.

This change makes it operate successfully, though I'm not sure if this is the best way of making the change.

Here's an example of the last couple streaming chunks from a GLM tool request:

    data: {"id":"chatcmpl-2bdf923fc05d4720b236bf42b780c095","object":"chat.completion.chunk","created":1759514500,"model":"zai-org/GLM-4.6","choices":[{"index":0,"delta":{"content":"","tool_calls":[{"id":"chatcmpl-tool-9e3c12e00d494ab49bd59359e9c231bb","type":"function","index":0,"function":{"name":"kubectl","arguments":"{\"command\": \"kubectl get deployments --all-namespaces\", \"modifies_resource\": \"no\"}"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2bdf923fc05d4720b236bf42b780c095","object":"chat.completion.chunk","created":1759514500,"model":"zai-org/GLM-4.6","choices":[{"index":0,"delta":{"content":""},"logprobs":null,"finish_reason":"tool_calls","stop_reason":151338,"token_ids":null}]}

Here's an example from a different open model (Qwen3-Next-80B-A3B-Instruct) served with vllm that already works with our existing code:

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"id":"chatcmpl-tool-4ff5f0260d154d29b924b158eff38e64","type":"function","index":0,"function":{"name":"kubectl"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"command\": \""}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"kubectl"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":" get"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":" namespaces"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":" create"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"-simple"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"-r"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"bac"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"\","}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":" \""}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"mod"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"ifies"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"_resource"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"\":"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":" \""}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"no"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"\"}"}}]},"logprobs":null,"finish_reason":null,"token_ids":null}]}

    data: {"id":"chatcmpl-2e4752429ee14412a83d57080fffa77c","object":"chat.completion.chunk","created":1759533916,"model":"Qwen/Qwen3-Next-80B-A3B-Instruct","choices":[{"index":0,"delta":{"content":""},"logprobs":null,"finish_reason":"tool_calls","stop_reason":null,"token_ids":null}]}