The createStreamFn callback hardcoded config.models.providers.ollama.baseUrl,
ignoring the actual provider ID from the context. When multiple Ollama providers
are configured on different ports (e.g. ollama on 11434, ollama2 on 11435), all
requests routed to the first provider's port.
Export resolveConfiguredOllamaProviderConfig from stream.ts and use it with the
ctx.provider parameter to dynamically look up the correct baseUrl per provider.
Closes#61678
