Add CloudXR VR streaming support for PICO 4 Ultra (Early Access)

Replaces manual H264/TCP stereo streaming with NVIDIA CloudXR for
higher-quality stereoscopic rendering and lower latency.

Changes:
- teleop_xr_agent.py: add --cloudxr flag (enables Isaac Sim XR mode,
  disables manual StreamingManager)
- deps/cloudxr/: NVIDIA CloudXR.js SDK (Early Access) with Isaac Lab
  teleop React web client
- deps/cloudxr/Dockerfile.wss.proxy: HAProxy WSS proxy for PICO 4 Ultra
  HTTPS mode (routes wss://48322 → ws://49100)
- deps/cloudxr/isaac/webpack.dev.js: disable file watching to avoid
  EMFILE errors with large node_modules
- deps/cloudxr/INSTALL.md: full setup guide

Usage:
  # Start CloudXR Runtime + Isaac Lab
  cd ~/IsaacLab && ./docker/container.py start \
      --files docker-compose.cloudxr-runtime.patch.yaml \
      --env-file .env.cloudxr-runtime

  # Run teleop with CloudXR
  ~/IsaacLab/isaaclab.sh -p teleop_xr_agent.py \
      --task Isaac-MindRobot-2i-DualArm-IK-Abs-v0 --cloudxr

  # Serve web client
  cd deps/cloudxr/isaac && npm run dev-server:https

deps/cloudxr/react/public/controller-icons.svg

@@ -0,0 +1,13 @@
+<svg width="24" height="24" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">
+  <!-- Diamond (top-left) -->
+  <polygon points="6,2 10,6 6,10 2,6" fill="black"/>
+  
+  <!-- Triangle (top-right) -->
+  <polygon points="18,2 22,10 14,10" fill="black"/>
+  
+  <!-- Circle (bottom-left) -->
+  <circle cx="6" cy="18" r="4" fill="black"/>
+  
+  <!-- Square (bottom-right) -->
+  <rect x="14" y="14" width="8" height="8" fill="black"/>
+</svg>