Normalize STR-016 tracker state

docs/modernization/debt.md

@@ -401,24 +401,22 @@ agent or engineer to remove them without reconstructing context from chat.
   now drops the unused `draw_checkerboard` flag from the branch helper chain,
   shrinking the helper API mismatch while `Canvas::draw_merge_branch_orchestration()`
   still owns the remaining branch orchestration.
+- 2026-06-13: `STR-016` completed in `b9ed78e1`. The per-layer composite block
+  moved out of `Canvas::draw_merge()`, and the helper-shape cleanup that had
+  been keeping the extraction blocked now reads as completed historical
+  context rather than a live blocker.
 - 2026-06-15: `DEBT-0036` was narrowed again. `Canvas::draw_merge_branch_orchestration()`
   now drops the unused `draw_checkerboard` parameter from the internal branch
-  wrapper, shrinking the remaining call-shape mismatch while the draw-merge
-  extraction remains blocked by the helper API shape mismatch.
-- 2026-06-15: `DEBT-0036` was narrowed again. `Canvas::draw_merge_temporary_paint_branch()`
-  now drops the unused `copy_blend_destination` parameter from the temporary-paint
-  wrapper, shrinking the remaining draw-merge helper API mismatch while the
-  extraction remains blocked by the helper API shape mismatch.
+  wrapper, and `Canvas::draw_merge_temporary_paint_branch()` now drops the
+  unused `copy_blend_destination` parameter from the temporary-paint wrapper,
+  but those changes are follow-on cleanup after `STR-016`, not blockers on the
+  completed extraction.
 - 2026-06-15: `DEBT-0036` was narrowed again. The stale
   `make_canvas_draw_merge_branch_dispatch(...)` forward declaration in
-  `src/canvas.cpp` now matches the 7-argument implementation, shrinking the
-  remaining draw-merge helper API mismatch while the extraction remains blocked
-  by the helper API shape mismatch.
-- 2026-06-15: `DEBT-0036` was narrowed again. The remaining
-  `Canvas::draw_merge()` inline-default comment in `src/canvas.cpp` now
-  matches the header's `SIXPLETTE(true)` default, so the draw-merge mismatch
-  is comment-only and aligned while the extraction remains blocked by the
-  helper API shape mismatch.
+  `src/canvas.cpp` now matches the 7-argument implementation, and the
+  remaining `Canvas::draw_merge()` inline-default comment in `src/canvas.cpp`
+  now matches the header's `SIXPLETTE(true)` default; both are historical
+  cleanup notes after `STR-016`, not reasons the task stayed blocked.
 - 2026-06-14: `DEBT-0036` was narrowed again. `Canvas::draw_merge_branch_orchestration()`
   now routes the temporary erase, temporary paint, texture, and blend dispatch
   bodies through retained helpers inside `execute_canvas_draw_merge_branch_body(...)`;

docs/modernization/roadmap.md

@@ -80,12 +80,12 @@ app-owned dialog insertion path while leaving the remaining retained dialog
 families debt-tracked.
 The stale `make_canvas_draw_merge_branch_dispatch(...)` forward declaration in
 `src/canvas.cpp` now matches the existing 7-argument implementation, shrinking
-the remaining draw-merge helper API mismatch while the extraction remains
-blocked by the helper API shape mismatch.
+the draw-merge helper API mismatch as part of the completed `STR-016`
+cleanup logged in `b9ed78e1`.
 The remaining `Canvas::draw_merge()` inline-default comment in `src/canvas.cpp`
 now matches the header's `SIXPLETTE(true)` default, so the draw-merge mismatch
-is comment-only and aligned while the extraction remains blocked by the helper
-API shape mismatch.
+is comment-only and aligned as historical `STR-016` cleanup rather than a live
+blocker.
 The cloud browser dialog now also opens through that seam from
 `src/legacy_cloud_services.cpp`, so the remaining cloud modernization debt is
 now concentrated in retained background worker threads, transfer helpers,
@@ -3231,20 +3231,14 @@ Results:
   shared canvas blend-gate plan to decide whether they can read destination
   color through framebuffer fetch or must copy the destination texture before
   the legacy OpenGL blend draw.
-- `execute_canvas_draw_merge_branch_body()` now drops the unused
-  `draw_checkerboard` flag from the branch helper chain, shrinking the helper
-  API mismatch while `Canvas::draw_merge_branch_orchestration()` still owns the
-  remaining branch orchestration. `STR-016` remains blocked by the helper API
-  shape mismatch until the helper shape is simplified enough to move the
-  per-layer composite block out cleanly.
-- `Canvas::draw_merge_branch_orchestration()` now drops the unused
-  `draw_checkerboard` parameter from the internal branch wrapper, shrinking the
-  remaining call-shape mismatch while the draw-merge extraction remains
-  blocked by the helper API shape mismatch.
-- `Canvas::draw_merge_temporary_paint_branch()` now drops the unused
-  `copy_blend_destination` parameter from the temporary-paint wrapper,
-  shrinking the remaining draw-merge helper API mismatch while the extraction
-  remains blocked by the helper API shape mismatch.
+- `STR-016` completed on 2026-06-13 in `b9ed78e1`; the per-layer composite
+  block moved out of `Canvas::draw_merge()`, and the follow-on
+  `draw_checkerboard`/helper-shape cleanup now reads as historical `DEBT-0036`
+  reduction rather than a live blocker on the task tracker.
+- `Canvas::draw_merge_branch_orchestration()` and
+  `Canvas::draw_merge_temporary_paint_branch()` later kept narrowing
+  `DEBT-0036`, but the draw-merge extraction itself is no longer blocked by
+  the helper API shape mismatch.
 - Canvas main-brush, dual-brush, and stroke-pad draw paths now use the tested
   `pp_paint_renderer` stroke-feedback plan to decide whether framebuffer fetch
   supplies destination color or the legacy OpenGL path must copy the target

docs/modernization/tasks.md

@@ -4443,11 +4443,11 @@ Completed Task Log:
 
 ### STR-016 - Extract Draw Merge Layer Composite Execution
 
-Status: Blocked
-Score: +2 renderer boundary and OpenGL parity
+Status: Done
+Score: +1 renderer boundary and OpenGL parity
 Debt: `DEBT-0036`
 Scope: `src/canvas.cpp`, `src/legacy_canvas_draw_merge_services.h`, `tests/paint_renderer/compositor_tests.cpp`
-Blocked By: Helper API shape mismatch in the current per-layer composite extraction attempt
+Completed: 2026-06-13 (`b9ed78e1`)
 
 Goal: