Move stroke commit input binding behind service helper

docs/modernization/debt.md

@@ -108,6 +108,10 @@ agent or engineer to remove them without reconstructing context from chat.
 - 2026-06-13: `DEBT-0036` was narrowed again. `Canvas::stroke_commit()`
   now routes the commit-input texture role switch through a local helper,
   leaving the callsite with sequence planning plus retained callback wiring.
+- 2026-06-13: `DEBT-0036` was narrowed again. `Canvas::stroke_commit()`
+  now routes the commit-input texture role switch through a retained service
+  helper, leaving the callsite with sequence planning and concrete face
+  bindings only.
 - 2026-06-13: `DEBT-0036` was narrowed again. `NodeStrokePreview::draw_stroke_immediate()`
   now routes final composite execution and preview copy-back through a retained
   local wrapper, leaving the call site with only sequence wiring.

docs/modernization/tasks.md

@@ -653,6 +653,9 @@ Progress Notes:
 - 2026-06-13: `Canvas::stroke_commit()` now routes the commit-input texture
   role switch through a local helper, so the callsite no longer owns that
   inline texture binding bundle.
+- 2026-06-13: `Canvas::stroke_commit()` now routes the commit-input texture
+  role switch through a retained service helper, so the callsite only supplies
+  concrete face bindings.
 - 2026-06-13: `Canvas::stroke_draw_samples()` now reuses a retained destination
   texture dispatch helper for the live sample path; `Canvas` still owns the
   concrete face textures and callback execution.