Add custom faster-whisper service with anti-hallucination params

Off-the-shelf Whisper wrappers hardcode faster-whisper defaults that
cause cascading hallucinations on real dictations (2/13 runs against
ahmetoner v1.9.1). This thin FastAPI service mirrors the /asr interface
but fixes condition_on_previous_text=False, temperature=0.0, and
vad_filter=True so the Axum server can switch by changing WHISPER_URL.

whisper/Dockerfile

@@ -0,0 +1,21 @@
+FROM nvidia/cuda:12.1.0-cudnn8-runtime-ubuntu22.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    python3 python3-pip ffmpeg && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY main.py .
+
+ENV WHISPER_MODEL=large-v3-turbo \
+    WHISPER_COMPUTE_TYPE=float16 \
+    WHISPER_MODELS_DIR=/models
+
+VOLUME ["/models"]
+EXPOSE 9001
+
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "9001", "--workers", "1"]