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/simple/webpack.dev.js

@@ -0,0 +1,42 @@
+const { merge } = require('webpack-merge')
+const common = require('./webpack.common.js')
+const path = require('path')
+
+// Check if HTTPS mode is enabled via environment variable
+const useHttps = process.env.HTTPS === 'true'
+
+module.exports = merge(common, {
+    mode: 'development',
+    devtool: 'eval-source-map',
+    devServer: {
+        allowedHosts: 'all',
+        hot: true,
+        open: false,
+        port: 8080,
+        // Enable HTTPS with self-signed certificate when HTTPS=true
+        ...(useHttps && { server: 'https' }),
+        static: {
+            directory: path.join(__dirname, './build'),
+            watch: true,
+        },
+        watchFiles: {
+            paths: ['src/**/*', '../../build/**/*'],
+            options: {
+                usePolling: false,
+                ignored: /node_modules/,
+            },
+        },
+        client: {
+            progress: true,
+            overlay: {
+                errors: true,
+                warnings: false,
+            },
+        },
+        devMiddleware: {
+            writeToDisk: true,
+        },
+    },
+})
+
+console.log(module.exports);