feat: add exit confirmation dialog on back navigation

core-ui/src/main/java/hu/bbara/purefin/ui/common/dialog/ExitAppDialog.kt

@@ -0,0 +1,28 @@
+package hu.bbara.purefin.ui.common.dialog
+
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+
+@Composable
+fun ExitAppDialog(
+    onCloseConfirmed: () -> Unit,
+    onDismiss: () -> Unit
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text("Close app?") },
+        text = { Text("Are you sure?") },
+        confirmButton = {
+            TextButton(onClick = onCloseConfirmed) {
+                Text("Close")
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text("Cancel")
+            }
+        }
+    )
+}