### Summary
The Go Anthropic driver's `ChatStreamlyWithSender`
(internal/entity/models/anthropic.go) was a stub that always returned
`"no such method"`, so any caller requesting a streamed response from a
Claude model via the Go path failed outright — diverging from the Python
`AnthropicCV` driver, which already supports streaming.
This implements the method by opening the Messages API with
`stream=true` and parsing the SSE response via the shared
`ParseSSEStream` helper, forwarding `text_delta`/`thinking_delta`
content through the `sender` callback and treating `message_stop` as the
terminal event — consistent with the other Go drivers in this package
(e.g. Cohere).
Fixes#17333
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Co-authored-by: Abhay Yadav <abhayyadav@Abhays-MacBook-Air.local>
e91da6b214