Promote STR-012 preview final-pass task

docs/modernization/tasks.md

@@ -1058,6 +1058,32 @@ Completed Task Log:
 
 ### STR-010 - Extract Remaining Draw Merge Composite Orchestration
 
+### STR-012 - Extract Preview Final Composite Orchestration
+
+Status: Ready
+Score: no score movement
+Debt: `DEBT-0036`
+Scope: `src/node_stroke_preview.cpp`, `tests/paint_renderer/compositor_tests.cpp`
+
+Goal:
+
+Extract the remaining preview final-composite and copy-back glue so the
+preview path keeps only concrete texture binding and pass ordering.
+
+Done Checks:
+
+- `NodeStrokePreview::draw_stroke_immediate()` no longer owns the final
+  composite and preview copy-back orchestration inline.
+- Regression coverage proves final composite and preview copy order.
+- `DEBT-0036` records the reduced preview final-pass surface.
+
+Validation:
+
+```powershell
+ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_compositor|pp_paint_renderer_stroke_execution" --output-on-failure
+cmake --build --preset windows-msvc-default --config Debug --target PanoPainter
+```
+
 Status: Done
 Score: +2 renderer boundary and OpenGL parity
 Debt: `DEBT-0036`