build(android): configure release signing config with key.properties

frontend/.gitignore

@@ -46,3 +46,4 @@ app.*.map.json
 /android/app/profile
 /android/app/release
 /android/app/google-services.json
+/android/key.properties

frontend/android/app/build.gradle.kts

@@ -1,3 +1,6 @@
+import java.io.FileInputStream
+import java.util.Properties
+
 plugins {
     id("com.android.application")
     id("com.google.gms.google-services")
@@ -5,6 +8,12 @@ plugins {
     id("dev.flutter.flutter-gradle-plugin")
 }
 
+val keystorePropertiesFile = rootProject.file("key.properties")
+val keystoreProperties = Properties()
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(FileInputStream(keystorePropertiesFile))
+}
+
 android {
     namespace = "com.teamsb.tis_rms"
     compileSdk = flutter.compileSdkVersion
@@ -31,11 +40,22 @@ android {
         versionName = flutter.versionName
     }
 
+    signingConfigs {
+        create("release") {
+            keyAlias = keystoreProperties.getProperty("keyAlias")
+            keyPassword = keystoreProperties.getProperty("keyPassword")
+            storeFile = keystoreProperties.getProperty("storeFile")?.let { file(it) }
+            storePassword = keystoreProperties.getProperty("storePassword")
+        }
+    }
+
     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.getByName("debug")
+            signingConfig = if (keystorePropertiesFile.exists()) {
+                signingConfigs.getByName("release")
+            } else {
+                signingConfigs.getByName("debug")
+            }
         }
     }
 }

frontend/android/key.properties.example

@@ -0,0 +1,4 @@
+storePassword=tis_rms_2026
+keyPassword=tis_rms_2026
+keyAlias=upload
+storeFile=upload-keystore.jks