Move early canvas GL mappings to renderer gl

docs/modernization/build-inventory.md

@@ -214,6 +214,10 @@ Known local toolchain state:
   brush/stencil/mix sampler filters and wraps, and image channel-count texture
   formats for cube-strip imports. Clamp-to-border sampler wrap is now part of
   the backend capability catalog and test coverage.
+  Early canvas draw helpers also consume backend-owned pick readback
+  format/type, stroke mixer depth/scissor/blend state, saved viewport and
+  clear-state queries, active texture units, fallback 2D texture unbind
+  targets, and stroke background copy targets.
 - `windows-msvc-vcpkg-headless` validates manifest install/configure/build/test
   for the current headless component matrix; see DEBT-0007 for remaining app
   and platform triplet migration.