Add SURYA_STREAM_MODE streaming (off/on/abort) for chat completions

- _generate_one_stream: streams responses, optional live repeat-loop
  detection (abort) that closes the stream early and flags the partial
  result as repeat=True so the existing retry loop re-runs with higher
  temperature
- _should_retry honors result.repeat; stream_mode threaded through both
  first attempt and retry calls in chat_completions_batch
- GenerationResult.repeat field; SURYA_STREAM_MODE setting (default off)
- diagnostic retry logs (reason=repeat|error|detected, temp)
- docker-compose: SURYA_STREAM_MODE=off, 4090 GPU profile, logs volume
- logger.yaml: TimedRotatingFileHandler for error handler (fixes startup
  crash without maxBytes)

vllm_tools.py

@@ -14,6 +14,7 @@ os.environ.setdefault("SURYA_INFERENCE_AUTOSTART", "false")
 os.environ.setdefault("SURYA_INFERENCE_KEEP_ALIVE", "false")
 os.environ.setdefault("SURYA_INFERENCE_LOGPROBS", "false")
 os.environ.setdefault("SURYA_INFERENCE_MAX_RETRIES", "1")
+os.environ.setdefault("SURYA_STREAM_MODE", "off")
 os.environ.setdefault("SURYA_INFERENCE_PARALLEL", "8")
 os.environ.setdefault("SURYA_MAX_TOKENS_FULL_PAGE", "6144")
 os.environ.setdefault("SURYA_MAX_BLOCKS_PER_PAGE", "80")