Add debug logging for incoming MIDI events

src/app_task.cpp

@@ -40,6 +40,9 @@ void AppTask::update() {
 }
 
 void AppTask::process_midi_event(const MidiEvent& event) {
+    Serial.printf("[APP] MIDI IN: Type=%d Ch=%d Note=%d Vel=%d\n",
+                  event.type, event.channel, event.data1, event.data2);
+    
     uint8_t led_index = 0xFF;
     uint8_t midi_channel = event.channel;
     uint8_t midi_note = event.data1;