Fix embed use-after-free, restore golden fixture + refs tests, drop dead note_entry

src/core/instrument/ui/curve_popup.h

@@ -6,7 +6,7 @@
 // focused sub-editor, not a view change): width/height each clamp to a fraction of the
 // window within min/max bounds. A title row sits over the curve box. The curve box rect
 // here is the border rect — the shell derives the mapping box via its curveBoxFromRect
-// formula, so the popup editor and the Zone-panel inline editor share coordinates.
+// formula.
 
 #pragma once
 

src/core/instrument/ui/envelope_edit.h

@@ -3,8 +3,9 @@
 // outside the DAW; the shell draws handles, captures the grab, and feeds pixel deltas back in.
 //
 // envelope_overlay owns the params->polyline forward (draw) map; this module owns the inverse
-// (edit) map + hit-test. Both read/write the same AmpEnvelope fields (shell re-reads the zone
-// every paint), so a node drag and a slider edit are two views on one source of truth.
+// (edit) map + hit-test. Both read/write the same AmpEnvelope fields (shell re-reads the one
+// parameter set every paint), so a node drag and a slider edit are two views on one source of
+// truth.
 //
 // A drag can never produce a param a slider couldn't: nodes are monotonic in time (clamped
 // between time predecessor/successor) and range-clamped to the same per-param [min,max] the

src/core/instrument/ui/envelope_overlay.h

@@ -1,7 +1,8 @@
 // envelope_overlay.h — amp-envelope -> polyline geometry for the Sample-view envelope overlay.
 // Engine-free by design (no sample_map/sampler_core dependency); mirror of waveform_view /
-// param_slider. The shell packs the zone's AdsrSeconds/TriggerParams into AmpEnvelope and draws
-// the polyline plus a handle at each node (envelope_edit does the hit-test).
+// param_slider. The shell packs the one parameter set's AdsrSeconds/TriggerParams into
+// AmpEnvelope and draws the polyline plus a handle at each node (envelope_edit does the
+// hit-test).
 
 #pragma once