fix: back button should take you to the previous screen instead of quitting the app.

app/src/main/kotlin/ca/ksamad/encore/ui/EncoreApp.kt

@@ -1,5 +1,6 @@
 package ca.ksamad.encore.ui
 
+import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
@@ -75,6 +76,18 @@ fun EncoreApp(vm: PlayerViewModel = viewModel()) {
         }
 
         is AppScreen.Player -> {
+            // The overlays form a back stack the OS knows nothing about (we don't use a
+            // nav library). Intercept the system/gesture back button and pop one level so
+            // it mirrors the on-screen back arrow, instead of falling through and closing
+            // the app. Only enabled when there's somewhere to pop back to.
+            BackHandler(enabled = overlay != PlayerOverlay.None) {
+                if (detailAlbum != null) {
+                    detailAlbum = null
+                } else {
+                    overlay = PlayerOverlay.None
+                }
+            }
+
             when (overlay) {
                 PlayerOverlay.Settings -> {
                     SettingsScreen(vm, onBack = { overlay = PlayerOverlay.None })