feat(build): enhance Gradle configuration with keystore properties and release signing setup

android/app/build.gradle

@@ -5,40 +5,73 @@ plugins {
     id "dev.flutter.flutter-gradle-plugin"
 }
 
+// Load keystore properties from key.properties file
+def keystoreProperties = new Properties()
+def keystorePropertiesFile = rootProject.file('key.properties')
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
+}
+
 android {
-    namespace = "com.example.marco"
+    // Define the namespace for your Android application
+    namespace = "com.marco.aiot"
+    // Set the compile SDK version based on Flutter's configuration
     compileSdk = flutter.compileSdkVersion
+    // Set the NDK version based on Flutter's configuration
     ndkVersion = flutter.ndkVersion
 
+    // Configure Java compatibility options
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_1_8
         targetCompatibility = JavaVersion.VERSION_1_8
     }
 
+    // Configure Kotlin options for JVM target
     kotlinOptions {
         jvmTarget = JavaVersion.VERSION_1_8
     }
 
+    // Default configuration for your application
     defaultConfig {
-        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId = "com.example.marcostage"
-        // You can update the following values to match your application needs.
-        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        // Specify your unique Application ID. This identifies your app on Google Play.
+        applicationId = "com.marco.aiotstage"
+        // Set minimum and target SDK versions based on Flutter's configuration
         minSdk = flutter.minSdkVersion
         targetSdk = flutter.targetSdkVersion
+        // Set version code and name based on Flutter's configuration (from pubspec.yaml)
         versionCode = flutter.versionCode
         versionName = flutter.versionName
     }
 
+    // Define signing configurations for different build types
+    signingConfigs {
+        release {
+            // Reference the key alias from key.properties
+            keyAlias keystoreProperties['keyAlias']
+            // Reference the key password from key.properties
+            keyPassword keystoreProperties['keyPassword']
+            // Reference the keystore file path from key.properties
+            storeFile file(keystoreProperties['storeFile'])
+            // Reference the keystore password from key.properties
+            storePassword keystoreProperties['storePassword']
+        }
+    }
+
+    // Define different build types (e.g., debug, release)
     buildTypes {
         release {
-            // TODO: Add your own signing config for the release build.
-            // Signing with the debug keys for now, so `flutter run --release` works.
-            signingConfig = signingConfigs.debug
+            // Apply the 'release' signing configuration defined above to the release build
+            signingConfig signingConfigs.release
+            // Enable code minification to reduce app size
+            minifyEnabled true
+            // Enable resource shrinking to remove unused resources
+            shrinkResources true
+            // Other release specific configurations can be added here, e.g., ProGuard rules
         }
     }
 }
 
+// Configure Flutter specific settings, pointing to the root of your Flutter project
 flutter {
     source = "../.."
 }