Extract stroke dirty bounds planning

docs/modernization/debt.md

@@ -18,6 +18,11 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Recent Reductions
 
+- 2026-06-13: DEBT-0036 was narrowed again. Stroke sample copy bounds, live
+  face dirty-box accumulation, and preview padding region math now live as
+  tested `pp_paint_renderer` planners and are consumed by retained Canvas and
+  stroke sample execution adapters. Canvas/preview still own GL ordering,
+  RTT/texture binding, history mutation, and final dirty state storage.
 - 2026-06-12: DEBT-0036 was narrowed again. `Canvas::stroke_commit` now reuses
   `legacy_canvas_stroke_composite_services.h` for commit-time final stroke
   `kShader::CompDraw` binding and composite/pattern/dual uniform writes.

docs/modernization/roadmap.md

@@ -1354,8 +1354,11 @@ stroke composite `kShader::CompDraw` setup now pass through
 reuses that same composite service for commit-time final stroke compositing.
 Stroke padding and commit dilate `kShader::StrokePad`/`kShader::StrokeDilate`
 setup now pass through `legacy_canvas_stroke_edge_services.h`, leaving
-RTT/texture ownership, dirty-box policy, checkerboard/non-stroke composite
-shaders, quad expansion, and retained callback execution under `DEBT-0036`.
+RTT/texture ownership, checkerboard/non-stroke composite shaders, and retained
+callback execution under `DEBT-0036`. Stroke sample copy bounds, live face
+dirty-box accumulation, and preview padding region math now live as tested
+`pp_paint_renderer` planners while retained Canvas/preview code still owns GL
+ordering, RTT/texture binding, history mutation, and final dirty state storage.
 It also owns renderer API texture-format to
 OpenGL internal/pixel/component token mapping, including depth-stencil formats,
 for future backend texture objects. `Texture2D` 2D texture binding, upload,