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+- Fixed `ElevenLabsTTSService` incorrectly enabling `auto_mode` when using `TextAggregationMode.TOKEN`. Auto mode disables server-side buffering and is designed for complete sentences — enabling it with token streaming degraded speech quality. The default is now derived automatically from the aggregation strategy: `auto_mode=True` for `SENTENCE`, `auto_mode=False` for `TOKEN`. Callers can still override by passing `auto_mode` explicitly.