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>

sexp_effects/parser.py

@@ -385,9 +385,9 @@ def _serialize_pretty(expr: List, indent: int) -> str:
 
 
 def parse_file(path: str) -> Any:
-    """Parse an S-expression file."""
+    """Parse an S-expression file (supports multiple top-level expressions)."""
     with open(path, 'r') as f:
-        return parse(f.read())
+        return parse_all(f.read())
 
 
 def to_sexp(obj: Any) -> str: