ray_vcn_bridge.py: Ray transport for the VCN-LUPINE bridge.
Replaces GPUNodeConnection TCP/MKV transport with Ray ObjectRef.
FrameDispatcher, BraidBackend, CUDABackend are unchanged — only
the wire between daemon and GPU node changes.
- RayBraidBackend: compute actor matching VCNBraidBackend pattern
- RayCUDABackend: GPU actor with /dev/dri (Mesa, no NVIDIA plugin)
- RayVCNBridge: full bridge as Ray actor (replaces daemon)
- RayGPUNodeConnection: drop-in for GPUNodeConnection
- SyncBraidWrapper/SyncCUDAWrapper: bridge Ray actors to sync interface
STRAND 42B → 63B, CROSSING 42B → 22B, PIST 24B → 57B
Batch 10: 5ms (0.5ms/frame), 10/10 non-empty
