Ω-W1-T5 review fixes: unify the drag frame resolve onto frameToX/xToFrame; honest comments on grabbableMarks and the grey-loop-mark contrast trade

src/shell/instrument/editor_controls.cpp

@@ -164,9 +164,11 @@ instrument::ui::WaveMarks ReaSamplerEditor::waveMarksFor(const SetupMarkers& m)
 }
 
 instrument::ui::WaveMarks ReaSamplerEditor::grabbableMarks(const SetupMarkers& m) const {
-    // Drawn IFF grabbable. Kept as its own fold because paint and hit-test stay separate
-    // questions, but do NOT re-add a suppression here: the Gate-with-loop-off marks are drawn
-    // grey precisely so they can still be dragged, and dragging one is what turns the enable on.
+    // Drawn IFF grabbable is the product rule, so this is an exact alias of waveMarksFor and
+    // cannot currently diverge from it. Kept as its own seam anyway because paint and hit-test
+    // are separate questions in principle — but do NOT re-add a suppression here: the
+    // Gate-with-loop-off marks are drawn grey precisely so they can still be dragged, and
+    // dragging one is what turns the enable on.
     return waveMarksFor(m);
 }