fix(ci): read key.properties for release signing with Kotlin imports

android/app/build.gradle.kts

@@ -1,9 +1,18 @@
+import java.util.Properties
+import java.io.FileInputStream
+
 plugins {
     id("com.android.application")
     id("kotlin-android")
     id("dev.flutter.flutter-gradle-plugin")
 }
 
+val keystorePropertiesFile = rootProject.file("key.properties")
+val keystoreProperties = Properties()
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(FileInputStream(keystorePropertiesFile))
+}
+
 android {
     namespace = "es.freetimelab.farolero.game"
     compileSdk = flutter.compileSdkVersion
@@ -26,9 +35,24 @@ android {
         versionName = flutter.versionName
     }
 
+    signingConfigs {
+        if (keystorePropertiesFile.exists()) {
+            create("release") {
+                keyAlias = keystoreProperties.getProperty("keyAlias") ?: ""
+                keyPassword = keystoreProperties.getProperty("keyPassword") ?: ""
+                storeFile = keystoreProperties.getProperty("storeFile")?.let { file(it) }
+                storePassword = keystoreProperties.getProperty("storePassword") ?: ""
+            }
+        }
+    }
+
     buildTypes {
         release {
-            signingConfig = signingConfigs.getByName("debug")
+            signingConfig = if (keystorePropertiesFile.exists()) {
+                signingConfigs.getByName("release")
+            } else {
+                signingConfigs.getByName("debug")
+            }
         }
     }
 }