Improve handling of time and zero-pressure events in MIDI export

tests/ableton-midi.test.ts

@@ -99,11 +99,29 @@ test('builds native Live 10 Channel Pressure steps with raw values', () => {
       [1, 75],
       [1, 75],
       [1, 20],
+      [2, 20],
     ],
   );
   assert.deepEqual(envelope.LoopSlot, { Value: {} });
 });
 
+test('retains an unchanged zero-pressure event at its original time', () => {
+  const envelopes = buildMidiClipEnvelopes([midiEvent(48, 2, 0)], {
+    'ControllerTargets.129': { '@Id': 45123 },
+  });
+
+  assert.deepEqual(
+    envelopes[0].Automation.Events.FloatEvent.map((event: any) => [
+      event['@Time'],
+      event['@Value'],
+    ]),
+    [
+      [-63072000, 0],
+      [0.5, 0],
+    ],
+  );
+});
+
 test('routes each source curve only to its matching pad clip, including MIDI-only pads', () => {
   const source0 = midiEvent(24, 0, 30);
   const source1 = midiEvent(48, 1, 60);