Migrate Isaac Lab / Sim to use OVRTX

Background: Omniverse Kit feature development ends after v110. Sim Teleop sits
at the top of a dependency chain that bottoms out on Kit — Sim Teleop is built
on Isaac Lab, Isaac Lab on Isaac Sim, Isaac Sim on Kit — once Kit stops
evolving, the XR teleoperation stack stops evolving with it. Isaac Lab has
already begun migrating to the kitless, Omniverse-libraries-only path; Sim
Teleop must follow to stay viable.

The gap: The kitless path lacks XR support. It requires an OpenXR-compliant
renderer that integrates with CloudXR for headset streaming. Such a library,
built on the OVRTX renderer SDK, is under development by the rendering
team.

This initiative: Integrate that library into Sim Teleop's kitless path. Isaac
Lab creates and drives the XR cameras and render products, with the render
loop coupled to the physics step; IsaacTeleop consumes operator
head/hand/controller input on the shared OpenXR session; a kitless launcher
manages the CloudXR runtime and session lifecycle end-to-end. Done means an
operator in a headset teleoperates a robot in Isaac Lab at parity with the
Kit-based XR path, with no Kit dependency in the loop.