add: absorb soprano_to_rvc as regular subdirectory

Voice conversion pipeline (Soprano TTS → RVC) with Docker support.
Previously tracked as bare gitlink; removed .git/ directories and
absorbed into main repo for unified tracking.

Includes: Soprano TTS, RVC WebUI integration, Docker configs,
WebSocket API, and benchmark scripts.
Updated .gitignore to exclude large model weights (*.pth, *.pt, *.onnx, *.index).
287 files (3.1GB of ML weights properly excluded via gitignore).

soprano_to_rvc/Dockerfile.soprano

@@ -0,0 +1,63 @@
+# Dockerfile.soprano
+# Soprano TTS Server running on NVIDIA CUDA (GTX 1660)
+# Python: 3.11.14 | pip: 25.3
+FROM nvidia/cuda:11.8.0-runtime-ubuntu22.04
+
+# Set timezone non-interactively
+ENV DEBIAN_FRONTEND=noninteractive
+ENV TZ=UTC
+
+# Install Python 3.11.14 and dependencies
+RUN apt-get update && apt-get install -y \
+    software-properties-common \
+    && add-apt-repository ppa:deadsnakes/ppa \
+    && apt-get update && apt-get install -y \
+    python3.11=3.11.14-* \
+    python3.11-venv \
+    python3.11-dev \
+    python3-pip \
+    git \
+    wget \
+    build-essential \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set Python 3.11 as default
+RUN update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.11 1 && \
+    update-alternatives --install /usr/bin/python python /usr/bin/python3.11 1
+
+# Create app directory
+WORKDIR /app
+
+# Copy soprano source and server
+COPY soprano/ /app/soprano/
+COPY soprano_server.py /app/
+COPY requirements-soprano.txt /app/
+
+# Install Python dependencies - pin pip to 25.3
+RUN pip3 install --no-cache-dir --upgrade pip==25.3
+
+# Install PyTorch with CUDA 11.8 support
+RUN pip3 install --no-cache-dir \
+    torch==2.7.1+cu118 \
+    torchvision==0.22.1+cu118 \
+    torchaudio==2.7.1+cu118 \
+    --index-url https://download.pytorch.org/whl/cu118
+
+# Install requirements
+RUN pip3 install --no-cache-dir -r /app/requirements-soprano.txt
+
+# Install soprano from source with lmdeploy
+WORKDIR /app/soprano
+RUN pip3 install --no-cache-dir -e '.[lmdeploy]'
+
+WORKDIR /app
+
+# Expose ZMQ port (internal)
+EXPOSE 5555
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
+    CMD python3 -c "import zmq; ctx = zmq.Context(); s = ctx.socket(zmq.REQ); s.connect('tcp://localhost:5555'); s.close()" || exit 1
+
+# Run soprano server
+CMD ["python3", "soprano_server.py"]