[mataylor-nvidia]

Description

Move PPISP from the Newton, OVRTX, and Isaac RTX renderers into PpispProcessor, attached through CameraCfg.pipeline. Renderers supply raw HDR; the camera owns processing, persistent output storage, reset, and cleanup. Explicit CameraExposureCfg replaces exposure changes triggered by output selection.

This is the upper PR of the stack, based on isaac-sim/IsaacLab#8693. It is hosted in this fork because upstream repository rules prohibit creating the branch needed for a stacked base. After the lower PR merges, rebase this branch onto upstream develop and open its upstream PR.

Camera processing preserves calibration-compatible dimensions, RGB/RGBA view behavior, raw HDR publication when requested, and processing once per capture. Every camera applies its exposure before a renderer exports the shared stage. The changes preserve current develop's global-camera behavior.

Migration: replace CameraCfg.isp_cfg with PpispProcessorCfg in CameraCfg.pipeline; configure neutral RTX HDR with CameraExposureCfg(). Resolve USD-authored PPISP settings explicitly before construction. The new observation dictionary adapters are deferred.

Size

• Production: +627 / -629.
• Tests: +555 / -164, including numerical, ownership, capture, and lifecycle coverage.
• Documentation and changelog fragments: +153 / -37.
• Total: +1,335 / -830.

Validation

• 100 focused tests passed across camera contracts, exposure, render-context lifecycle, Isaac RTX contracts, PPISP numerical behavior, and OVRTX HDR/exposure routing. This includes CUDA shared-controller weights and current-stream execution, plus Newton rendering coverage. The 21 camera contract tests were rerun after syncing the lower PR compatibility cleanup.
• Repository formatting/lint, changelog validation against the lower branch, and Git LFS pointer checks passed.
• Clean focused Sphinx validation of the five affected API/concept pages passed. Full-site documentation stopped at the installed Omniverse Kit EULA requirement; the focused build omits cross-links to excluded pages and full-site source-link generation.
• Full live OVRTX/Isaac RTX and remote GPU CI were not run. Keep this PR in draft pending integration validation.

Type of change

• Breaking change
• Documentation update

Release backport

• Backport this pull request to the active release branch after it merges into develop