desktop: parse and discard RSP_KEEPALIVE messages

cue/src/app.rs

@@ -734,6 +734,7 @@ impl App {
                     self.cal_cell_constant = Some(k);
                     self.status = format!("Device cell constant: {:.4} cm-1", k);
                 }
+                EisMessage::Keepalive => {}
             },
             Message::TabSelected(t) => {
                 if t == Tab::Browse {

cue/src/protocol.rs

@@ -26,6 +26,7 @@ pub const RSP_REF_LP_RANGE: u8 = 0x21;
 pub const RSP_REFS_DONE: u8 = 0x22;
 pub const RSP_CELL_K: u8 = 0x11;
 pub const RSP_REF_STATUS: u8 = 0x23;
+pub const RSP_KEEPALIVE: u8 = 0x50;
 
 /* Cue → ESP32 */
 pub const CMD_SET_SWEEP: u8 = 0x10;
@@ -258,6 +259,7 @@ pub enum EisMessage {
     RefsDone,
     RefStatus { has_refs: bool },
     CellK(f32),
+    Keepalive,
 }
 
 fn decode_u16(data: &[u8]) -> u16 {
@@ -413,6 +415,7 @@ pub fn parse_sysex(data: &[u8]) -> Option<EisMessage> {
             let p = &data[2..];
             Some(EisMessage::CellK(decode_float(&p[0..5])))
         }
+        RSP_KEEPALIVE => Some(EisMessage::Keepalive),
         _ => None,
     }
 }