fix(voice): Trigger legato keys on held-stack depth, CC123 allNotesOff clears mono stack, voice-param edits rebuild from decoded PCM (no re-decode), mono sizes 1 shifter ring

src/vst/sampler_core.h

@@ -568,6 +568,14 @@ public:
     // the older tail to ring — matches hardware behavior). No-op if none match.
     void noteOff(int note);
 
+    // PANIC / MIDI All-Notes-Off (CC 123). Clears the MONO held stack and releases EVERY
+    // active voice: Gate voices enter their release tail; Trigger one-shots ignore release
+    // by design and play through their bounded play length (they can never be stuck). This
+    // is the mono stack's ONLY reset path — a phantom entry left by a lost note-off would
+    // otherwise be resurrected by the next fallback and sustain forever with no key held.
+    // RT-safe (no allocation, bounded by maxVoices); callable from the audio thread.
+    void allNotesOff();
+
     // REAL-TIME render (S4): sums all active voices into the caller-provided buffer
     // `out[0..frameCount)`, ADDING to whatever is there (the caller clears or mixes —
     // this never touches memory it does not own and NEVER allocates). This is the
@@ -619,7 +627,8 @@ private:
     struct HeldNote { std::uint8_t note; std::uint8_t velocity; };
 
     // Mono note-on: push to the stack and take the voice over (legato retune on a same-sample
-    // takeover, else a fresh start). Returns 0 (the mono voice) or kNoVoice for out-of-zone.
+    // takeover, else a fresh start). Returns 0 (the mono voice) or kNoVoice for out-of-zone
+    // or out-of-range (note outside [0,127] — rejected BEFORE the stack, which stores uint8).
     // The S16 Preserve cap is NOT applied in mono — a single voice runs at most one shifter,
     // inherently within any cap; applying it would wrongly drop a Preserve->Preserve takeover.
     std::size_t monoNoteOn(int note, int velocity);
@@ -671,6 +680,9 @@ public:
     // Release the preview IF `note` is the one sounding (a stale off for a replaced note is a
     // no-op). Gate zones enter release; Trigger zones ignore note-off and play through.
     void noteOff(int note);
+    // PANIC peer of VoiceEngine::allNotesOff: release the ringing preview UNCONDITIONALLY,
+    // whatever note it is on. Gate enters release; Trigger plays through (bounded). RT-safe.
+    void releaseAll();
 
     bool active() const { return voice_.active(); }