Normalize STR-016 tracker state

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