fix(discovery): stop scan immediately without blocking on radio reconnect

- Moves  into a detached CoroutineScope within .
- Prevents the UI from being stuck in 'Restoring home preset...' (and making the user think the scan is still in progress) for up to 60 seconds while the radio reboots and reconnects over BLE.
- Removes  state manipulation from  to prevent it from overwriting the  state when stopped manually.

Author: jamesarich

feature/discovery/src/commonMain/kotlin/org/meshtastic/feature/discovery/DiscoveryScanEngine.kt

@@ -20,6 +20,7 @@ package org.meshtastic.feature.discovery
 
 import co.touchlab.kermit.Logger
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
@@ -183,10 +184,14 @@ class DiscoveryScanEngine(
             if (!isActive) return
             Logger.i { "DiscoveryScanEngine: stopping scan" }
             cancelScanInternal()
-            persistCurrentDwellResults()
+        }
+        persistCurrentDwellResults()
+        finalizeSession("stopped")
+        _scanState.value = DiscoveryScanState.Idle
+
+        // Restore home preset in the background so we don't block the UI with the connection wait
+        CoroutineScope(Dispatchers.Default).launch {
             restoreHomePreset()
-            finalizeSession("stopped")
-            _scanState.value = DiscoveryScanState.Idle
         }
     }
 
@@ -505,7 +510,6 @@ class DiscoveryScanEngine(
 
     private suspend fun restoreHomePreset() {
         val preset = homePreset ?: return
-        _scanState.value = DiscoveryScanState.Restoring
         shiftPreset(preset)
         // Wait briefly for reconnection after restoring
         waitForConnection()