fix(mesh): probe retries across the listener's port-hold windows

Linux double-opens ttys, so a probe racing the reconnect loop corrupted
both handshakes into silence (framework-pt, real Reticulum stick). Three
attempts 7s apart land in the listener's backoff gaps.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/mesh/listener/session.rs

@@ -366,6 +366,25 @@ pub struct DeviceProbe {
 /// loop can pick the device up afterwards. Reticulum uses the bare KISS
 /// DETECT probe — no daemon spawn just to identify a stick.
 pub(crate) async fn probe_device(path: &str) -> Result<DeviceProbe> {
+    // The listener's reconnect loop may hold this port for ~10s of every
+    // backoff cycle, and Linux happily double-opens a tty — two concurrent
+    // handshakes corrupt each other into silence (observed on framework-pt:
+    // every firmware "failed" while the listener was mid-cycle). Retry across
+    // the listener's idle gaps instead of failing on first collision.
+    let mut last_err = None;
+    for attempt in 0..3u32 {
+        if attempt > 0 {
+            tokio::time::sleep(Duration::from_secs(7)).await;
+        }
+        match probe_device_once(path).await {
+            Ok(p) => return Ok(p),
+            Err(e) => last_err = Some(e),
+        }
+    }
+    Err(last_err.unwrap_or_else(|| anyhow::anyhow!("probe failed")))
+}
+
+async fn probe_device_once(path: &str) -> Result<DeviceProbe> {
     if super::super::reticulum::probe_rnode(path).await.is_ok() {
         return Ok(DeviceProbe {
             path: path.to_string(),