instrument: latch the note done at the read-head run-off, fit the migrated fades, and lift the curve dial and overlay selection into pure modules

src/shell/instrument/reasampler_editor.h

@@ -81,10 +81,10 @@ private:
     enum class DragKind { kNone, kRootMarker, kWaveMarker, kScrollThumb, kEnvNode,
                           kCurveNode, kDeckKnob };
 
-    // Which envelope the waveform overlay is drawing and editing. Exclusive, and kNone is a
-    // valid resting state — the editor opens there. Transient view state: never persisted,
-    // never a parameter.
-    enum class OverlayEnv { kNone, kAmp, kPitch, kFilter };
+    // Which envelope the waveform overlay is drawing and editing. The selection type and its
+    // whole state machine are the pure deck_groups module's; this alias keeps the shell's
+    // spelling.
+    using OverlayEnv = instrument::ui::OverlayEnv;
 
     // Controls on the setup surface. The int value is the opaque control id the pure
     // knob_deck hit-test returns; the shell maps it to the one parameter set or a
@@ -335,10 +335,6 @@ private:
     // UNPACK (commit): an edited StageEnvelope -> the play params, in place.
     void unpackEnvelope(OverlayEnv which, const StageEnvelope& env, PlaySeconds& play) const;
 
-    // The radio control id that selects `which`, and its inverse. One table, so the deck's
-    // radio and the overlay can never drift apart.
-    static OverlayEnv overlayEnvForRadio(int radioId);
-
     // Clamp bounds envelope_edit uses, matching the sliders' own domains so a node drag can
     // never produce a param a slider couldn't.
     EnvClampBounds envClampBounds() const;