The buffered-body inter-chunk timeout was named llm_stream_chunk_timeout,
confusingly similar to stream_chunk_timeout (the SSE inter-chunk timeout).
Operators tuning "stream chunk timeout" would set the wrong env var.
Rename to llm_body_chunk_timeout / SPROUT_AGENT_LLM_BODY_CHUNK_TIMEOUT_SECS
to clearly distinguish the buffered path from the streaming path.
Extract the openai_to_sse_events test helper (duplicated in fake_llm.rs,
golden_transcripts.rs, and regressions.rs) into tests/common/mod.rs.
Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>