chore: report llm response chunk status

src/LlamaCppClient.php

src/LlamaCppClientResponseChunk.php

src/LlamaCppCompletionIterator.php

src/LlamaCppCompletionToken.php

src/ObservableTaskStatus.php

src/ObservableTaskTable.php

src/ObservableTaskTimeoutIterator.php

src/PromptSubjectResponderAggregate.php

src/PromptSubjectResponse.php

src/PromptSubjectResponseChunk.php

src/SubjectActionTokenReader.php

...cketRPCResponder/LlamaCppSubjectActionPromptResponder.php