Support CUDA 13 / RTX 5070 Ti

[Toluwani5778]

Hi Kokoro Team,

Currently, the Docker image uses CUDA 12.8. My RTX 5070 Ti requires CUDA 13, and PyTorch fails to load models with CUDA errors.
I tested a modified Dockerfile based on CUDA 13.0.1 + cuDNN and installing PyTorch with CUDA 13 wheels, and the model works correctly on newer GPUs.

Proposed changes:

• Update base image: nvcr.io/nvidia/cuda:13.0.1-cudnn-devel-ubuntu24.04
• Ensure PyTorch installs the CUDA 13 wheel: pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu13

This allows support for the latest GPUs (like RTX 5070 Ti) while keeping compatibility with the existing stack.

Thank you!

The modified dockerfile found at
docker/gpu/Dockerfile

# Use CUDA 13 base with cuDNN, Ubuntu 24.04
FROM --platform=$BUILDPLATFORM nvcr.io/nvidia/cuda:13.0.1-cudnn-devel-ubuntu24.04

# Enable universe repository and install dependencies
# Install dependencies
RUN apt-get update -y && \
    apt-get install -y software-properties-common && \
    add-apt-repository universe && \
    apt-get update -y && \
    apt-get install -y \
        python3 python3-venv python3-pip \
        espeak-ng espeak-ng-data \
        git libsndfile1 curl ffmpeg g++ cmake && \
    apt-get clean && rm -rf /var/lib/apt/lists/* && \
    mkdir -p /usr/share/espeak-ng-data && \
    ln -s /usr/lib/*/espeak-ng-data/* /usr/share/espeak-ng-data/ && \
    curl -LsSf https://astral.sh/uv/install.sh | sh && \
    mv /root/.local/bin/uv /usr/local/bin/ && \
    mv /root/.local/bin/uvx /usr/local/bin/ && \
    useradd -m -u 1001 appuser && \
    mkdir -p /app/api/src/models/v1_0 && \
    chown -R appuser:appuser /app

USER appuser
WORKDIR /app

# Copy dependency files
COPY --chown=appuser:appuser pyproject.toml ./pyproject.toml

# Install dependencies with GPU extras using system Python 3
RUN uv venv --python python3 && \
    uv sync --extra gpu --no-cache

# Copy project files including models
COPY --chown=appuser:appuser api ./api
COPY --chown=appuser:appuser web ./web
COPY --chown=appuser:appuser docker/scripts/ ./
RUN chmod +x ./entrypoint.sh

# Set environment variables
ENV PATH="/app/.venv/bin:$PATH" \
    PYTHONUNBUFFERED=1 \
    PYTHONPATH=/app:/app/api \
    UV_LINK_MODE=copy \
    USE_GPU=true \
    PHONEMIZER_ESPEAK_PATH=/usr/bin \
    PHONEMIZER_ESPEAK_DATA=/usr/share/espeak-ng-data \
    ESPEAK_DATA_PATH=/usr/share/espeak-ng-data \
    DEVICE="gpu"

ENV DOWNLOAD_MODEL=true

# Download model if enabled
RUN if [ "$DOWNLOAD_MODEL" = "true" ]; then \
    python download_model.py --output api/src/models/v1_0; \
    fi

# Run FastAPI server through entrypoint.sh
CMD ["./entrypoint.sh"]