Add IPFS HLS streaming and GPU optimizations

- Add IPFSHLSOutput class that uploads segments to IPFS as they're created
- Update streaming task to use IPFS HLS output for distributed streaming
- Add /ipfs-stream endpoint to get IPFS playlist URL
- Update /stream endpoint to redirect to IPFS when available
- Add GPU persistence mode (STREAMING_GPU_PERSIST=1) to keep frames on GPU
- Add hardware video decoding (NVDEC) support for faster video processing
- Add GPU-accelerated primitive libraries: blending_gpu, color_ops_gpu, geometry_gpu
- Add streaming_gpu module with GPUFrame class for tracking CPU/GPU data location
- Add Dockerfile.gpu for building GPU-enabled worker image

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

scripts/cloud-init-gpu.sh

@@ -0,0 +1,77 @@
+#!/bin/bash
+# Cloud-init startup script for GPU droplet (RTX 6000 Ada, etc.)
+# Paste this into DigitalOcean "User data" field when creating droplet
+
+set -e
+export DEBIAN_FRONTEND=noninteractive
+exec > /var/log/artdag-setup.log 2>&1
+
+echo "=== ArtDAG GPU Setup Started $(date) ==="
+
+# Update system (non-interactive, keep existing configs)
+apt-get update
+apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" upgrade
+
+# Install essentials
+apt-get install -y \
+    python3 python3-venv python3-pip \
+    git curl wget \
+    ffmpeg \
+    vulkan-tools \
+    build-essential
+
+# Create venv
+VENV_DIR="/opt/artdag-gpu"
+python3 -m venv "$VENV_DIR"
+source "$VENV_DIR/bin/activate"
+
+# Install Python packages
+pip install --upgrade pip
+pip install \
+    numpy \
+    opencv-python-headless \
+    wgpu \
+    httpx \
+    pyyaml \
+    celery[redis] \
+    fastapi \
+    uvicorn \
+    asyncpg
+
+# Create code directory
+mkdir -p "$VENV_DIR/celery/sexp_effects/effects"
+mkdir -p "$VENV_DIR/celery/sexp_effects/primitive_libs"
+mkdir -p "$VENV_DIR/celery/streaming"
+
+# Add SSH key for easier access (optional - add your key here)
+# echo "ssh-ed25519 AAAA... your-key" >> /root/.ssh/authorized_keys
+
+# Test GPU
+echo "=== GPU Info ==="
+nvidia-smi || echo "nvidia-smi not available yet"
+
+echo "=== NVENC Check ==="
+ffmpeg -encoders 2>/dev/null | grep -E "nvenc|cuda" || echo "NVENC not detected"
+
+echo "=== wgpu Check ==="
+"$VENV_DIR/bin/python3" -c "
+import wgpu
+try:
+    adapter = wgpu.gpu.request_adapter_sync(power_preference='high-performance')
+    print(f'GPU: {adapter.info}')
+except Exception as e:
+    print(f'wgpu error: {e}')
+" || echo "wgpu test failed"
+
+# Add environment setup
+cat >> /etc/profile.d/artdag-gpu.sh << 'ENVEOF'
+export WGPU_BACKEND_TYPE=Vulkan
+export PATH="/opt/artdag-gpu/bin:$PATH"
+ENVEOF
+
+# Mark setup complete
+touch /opt/artdag-gpu/.setup-complete
+echo "=== Setup Complete $(date) ==="
+echo "Venv: /opt/artdag-gpu"
+echo "Activate: source /opt/artdag-gpu/bin/activate"
+echo "Vulkan: export WGPU_BACKEND_TYPE=Vulkan"