Add local MeloTTS support

docker/melotts/Dockerfile

@@ -0,0 +1,18 @@
+FROM python:3.9-slim
+
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /opt/realtime-voice-bot
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  build-essential \
+  git \
+  libsndfile1 \
+  && rm -rf /var/lib/apt/lists/*
+
+RUN pip install --no-cache-dir git+https://github.com/myshell-ai/MeloTTS.git@v0.1.2
+RUN python -m unidic download
+
+COPY melo_tts_cli.py /opt/realtime-voice-bot/melo_tts_cli.py
+
+ENTRYPOINT ["python", "/opt/realtime-voice-bot/melo_tts_cli.py"]