Replace custom ViewportColorCorrector with stageView.py color correction

Remove the custom GL post-process (ViewportColorCorrector) that bypassed
HdxColorCorrectionTask. Instead pass colorCorrectionMode, ocioDisplay,
ocioView, ocioColorSpace, and ocioLook directly to UsdImagingGLRenderParams
and SetColorCorrectionSettings(), delegating correction to Hydra —
the same approach used in usdview's stageView.renderSinglePass().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/core/UsdSceneRenderer.h

@@ -25,10 +25,6 @@
 
 namespace UsdLayerManager {
 
-/// Custom viewport color-correction post-process (sRGB / OCIO) implemented in
-/// our own GL shader instead of HdxColorCorrectionTask.  Defined in the .cpp.
-class ViewportColorCorrector;
-
 /// Bounding box display mode for selected prims.
 enum class BBoxMode {
     None,           ///< No bounding boxes drawn
@@ -392,17 +388,6 @@ private:
     pxr::SdfPathVector m_cachedCameraPaths;
     bool               m_cameraCacheDirty = true;
 
-    // --- Custom color-correction post-process ---------------------------------
-    // The scene is rendered linear (Hydra correction "disabled") and corrected
-    // by our own GL shader, bypassing HdxColorCorrectionTask.  ApplyViewport-
-    // ColorCorrection() resolves the linear result into m_ccLinearTex, then
-    // draws a corrected fullscreen quad back into the draw-target FBO.
-    void ApplyViewportColorCorrection(int width, int height);
-    std::unique_ptr<ViewportColorCorrector> m_colorCorrector;
-    GLuint m_ccLinearFBO = 0;   ///< FBO wrapping m_ccLinearTex (correction input)
-    GLuint m_ccLinearTex = 0;   ///< single-sample linear copy of the Hydra output
-    int    m_ccLinearW   = 0;
-    int    m_ccLinearH   = 0;
 };
 
 } // namespace UsdLayerManager