[Model] Aura support - Non async chunk path (#4257)

Signed-off-by: Rein Yang <ruiruyang2@gmail.com>
Signed-off-by: R2-Y <ruiruyang2@gmail.com>

docs/user_guide/examples/online_serving/aura_omni.md

@@ -0,0 +1,65 @@
+# AURA Omni Pipeline
+
+`aura_omni` wires ASR, AURA, and Qwen3-TTS into one vLLM-Omni pipeline:
+
+```text
+ASR -> AURA -> Qwen3-TTS Talker -> Code2Wav
+```
+
+Qwen3-TTS remains two engine stages so the pipeline reuses the existing native
+Talker and Code2Wav implementation.
+
+```bash
+vllm serve aurateam/AURA \
+  --omni \
+  --deploy-config vllm_omni/deploy/aura_omni.yaml \
+  --served-model-name aurateam/AURA \
+  --trust-remote-code
+```
+
+Configure local checkpoints by editing per-stage `model` values in
+`vllm_omni/deploy/aura_omni.yaml`. The deploy file sets
+`pipeline: aura_omni`, so the four-stage topology is used even if the
+command-line `--model` points at one of the component checkpoints.
+
+Send requests with `"model": "aurateam/AURA"`. The ASR, AURA, and Qwen3-TTS
+checkpoint paths are internal stage models from the deploy YAML, not the
+OpenAI-facing served model name.
+
+The AURA stage can emit `<|silent|>`. Silent outputs are treated as a gate:
+they produce no Qwen3-TTS Talker input, so no audio is synthesized for that
+turn.
+
+## GPU Utilization Recommendation
+
+`gpu_memory_utilization` in `vllm_omni/deploy/aura_omni.yaml` controls how much
+VRAM each stage can reserve. Start with this split for a single GPU:
+
+- Stage 0 (ASR): `0.10`
+- Stage 1 (AURA): `0.40`
+- Stage 2 (Qwen3-TTS Talker): `0.20`
+- Stage 3 (Qwen3-TTS Code2Wav): `0.20`
+
+## TTS Modes
+
+`aura_omni` can pass AURA text to Qwen3-TTS in two task modes:
+
+- `Base`: voice clone from `tts_ref_audio` with ICL enabled in the AURA
+  pipeline. Provide both `tts_ref_audio` and `tts_ref_text`. Set
+  `tts_x_vector_only_mode=true` to disable ICL and use speaker embedding only.
+- `CustomVoice`: predefined speaker mode. Use a Qwen3-TTS CustomVoice
+  checkpoint for stages 2 and 3 in `aura_omni.yaml`, then pass
+  `tts_task_type=CustomVoice` and `tts_speaker`.
+
+By default, AURA responses are passed to Qwen3-TTS as text. Set
+`additional_information.tts_pass_token_ids=true` to pass AURA-generated
+assistant token ids directly instead. Even when token passthrough is disabled,
+the stage processor uses AURA token ids when available to estimate the Talker
+prefill length, so scheduling does not rely on raw character length.
+
+The example client exposes this as:
+
+```bash
+python examples/online_serving/aura_omni/openai_chat_completion_client.py \
+  --tts-pass-token-ids
+```