Route VR stroke setup through helpers

docs/modernization/debt.md

@@ -18,6 +18,10 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Recent Reductions
 
+- 2026-06-13: DEBT-0036 was narrowed again. Desktop VR retained temporary erase
+  and draw shader setup now route through the shared stroke erase/composite
+  helpers; VR still owns sampler/texture binding, per-eye/view transforms,
+  temporary stroke texture selection, and draw execution.
 - 2026-06-13: DEBT-0036 was narrowed again. `Canvas::stroke_commit` and
   `Canvas::draw_merge` retained `CompErase` shader setup now route through
   `legacy_canvas_stroke_erase_services.h`; Canvas still owns texture binding,

docs/modernization/roadmap.md

@@ -3013,6 +3013,10 @@ Results:
   now share the stroke erase shader setup helper, while texture binding, mask
   RTT binding, dirty/layer mutation, framebuffer feedback, and draw execution
   remain in retained Canvas code.
+- Desktop VR temporary erase/draw compositing now shares the retained stroke
+  erase and composite shader setup helpers, while sampler/texture binding,
+  per-eye/view transforms, temporary stroke texture selection, and draw
+  execution remain in retained VR code.
 - `Canvas::stroke_draw_mix` now shares the retained stroke composite shader
   helper for mixer-pass `CompDraw` setup, while preserving its caller-specific
   texture slot uniforms. Mixer framebuffer/scissor state, sampler and texture