fix(android): system back from trip replay returns to the list

android/app/src/main/java/com/yarisobd/app/MainActivity.kt

@@ -2,6 +2,7 @@ package com.yarisobd.app
 
 import android.os.Bundle
 import androidx.activity.ComponentActivity
+import androidx.activity.compose.BackHandler
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.compose.foundation.layout.Column
@@ -117,6 +118,20 @@ fun YarisMainScreen(client: OkHttpClient) {
         }
     }
 
+    // System back from a trip replay returns to the list instead of exiting.
+    BackHandler(enabled = selectedTrip != null || selectedPortalTrip != null) {
+        when {
+            selectedTrip != null -> {
+                selectedTrip = null
+                tripVm.clearRoute()
+            }
+            selectedPortalTrip != null -> {
+                selectedPortalTrip = null
+                portalVm.clearRoute()
+            }
+        }
+    }
+
     if (selectedTrip != null) {
         TripReplayScreen(
             trip = selectedTrip!!,