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/core/instrument/map/params_payload.cpp

@@ -61,15 +61,17 @@ void putAhd(std::vector<std::uint8_t>& out, const AhdSeconds& a) {
 }
 // THE lift of the retired Trigger fade pair onto the AHD that replaced it: Attack takes the
 // fade-in, Decay the fade-out, Hold the whole remainder — so a zero fade-out lands Decay = 0
-// and the abrupt end an old instance could express stays representable. The fades were SOURCE
-// frames and the AHD stores wall-clock seconds, so the conversion goes through the same
-// project rate the v3 lift already uses. A v10-or-newer blob overwrites this from its own tail.
+// and the abrupt end an old instance could express stays representable. The seconds conversion
+// and its rate-mismatch bound, and the two fitted exponents, are documented in
+// component_state_io.h. A v10-or-newer blob overwrites all five fields from its own tail.
 void liftTriggerFades(std::int64_t fadeInFrames, std::int64_t fadeOutFrames, double projectRate,
                       AhdSeconds& out) {
     const double rate = projectRate > 0.0 ? projectRate : 1.0;
     out.attackSeconds = static_cast<double>(fadeInFrames > 0 ? fadeInFrames : 0) / rate;
     out.decaySeconds  = static_cast<double>(fadeOutFrames > 0 ? fadeOutFrames : 0) / rate;
     out.holdFraction  = 1.0;
+    out.attackCurve   = kTriggerFadeLiftAttackCurve;
+    out.decayCurve    = kTriggerFadeLiftDecayCurve;
 }
 
 // Read the play tail (v5 shape onward) into `p`. Shared by the legacy zone reader and the