Route canvas mode render state through GL backend

docs/modernization/roadmap.md

@@ -2020,9 +2020,11 @@ Results:
   Eye framebuffer viewport execution in the retained HMD path also routes
   through tested `pp_renderer_gl` viewport dispatch.
 - Canvas mode overlay, mask, and transform paths now route generic OpenGL
-  blend/depth state, active texture units, 2D framebuffer-to-texture copy
-  dispatch, RGBA8 readback formats, and RTT-backed transform history region
-  readbacks through the renderer GL backend mapping.
+  blend/depth state execution, active texture unit switches, transform/cut
+  viewport execution, 2D framebuffer-to-texture copy dispatch, RGBA8 readback
+  formats, and RTT-backed transform history region readbacks through the
+  renderer GL backend mapping. The retained canvas-tip pick readback remains
+  direct legacy OpenGL until the readback boundary is finished under DEBT-0036.
 - `NodeCanvas` panorama UI rendering now routes sampler defaults, saved
   viewport/clear/blend/depth/scissor state, color clears, active texture units,
   fallback 2D texture unbinds, 2D framebuffer-to-texture copy dispatch, and