feat: GetMac command + MacAddress response

New protocol command (tag 8): GetMac returns the board's 6-byte hardware
address. Useful when multiple dongles are connected to one host.

Response (tag 6): MacAddress containing 6 raw bytes.

Updated: PROTOCOL.md, CHANGELOG, donglora.py decoder, all_commands.py.

src/protocol.rs

@@ -139,6 +139,7 @@ pub enum Command {
     },
     DisplayOn,
     DisplayOff,
+    GetMac,
 }
 
 impl Command {
@@ -178,6 +179,7 @@ impl Command {
             }
             6 => Some(Self::DisplayOn),
             7 => Some(Self::DisplayOff),
+            8 => Some(Self::GetMac),
             _ => None,
         }
     }
@@ -197,6 +199,7 @@ pub enum Response {
     TxDone,
     Ok,
     Error(ErrorCode),
+    MacAddress([u8; 6]),
 }
 
 impl Response {
@@ -232,6 +235,11 @@ impl Response {
                 buf[1] = code as u8;
                 2
             }
+            Self::MacAddress(mac) => {
+                buf[0] = 6;
+                buf[1..7].copy_from_slice(&mac);
+                7
+            }
         }
     }
 }

src/radio/task.rs

@@ -219,7 +219,7 @@ async fn handle_cmd(
             status.sender().send(state.clone());
             responses.send(Response::Ok).await;
         }
-        Command::DisplayOn | Command::DisplayOff => {}
+        Command::DisplayOn | Command::DisplayOff | Command::GetMac => {}
         Command::Transmit { config, payload } => {
             let tx_config = config.map(|c| c.resolve_power(Board::TX_POWER_RANGE)).or(state.config);
             if let Some(cfg) = tx_config {

src/usb/task.rs

@@ -207,6 +207,12 @@ async fn route_command(
                 responses.send(Response::Error(ErrorCode::NoDisplay)).await;
             }
         }
+        Command::GetMac => {
+            use crate::board::{Board, LoRaBoard};
+            responses
+                .send(Response::MacAddress(Board::mac_address()))
+                .await;
+        }
         other => {
             commands.send(other).await;
         }