chore: add release signing config via keystore.properties

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitignore

@@ -33,3 +33,4 @@ google-services.json
 # Android Profiling
 *.hprof
 
+keystore.properties

app/build.gradle.kts

@@ -1,3 +1,5 @@
+import java.util.Properties
+
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
@@ -5,7 +7,25 @@ plugins {
     alias(libs.plugins.ksp)
 }
 
+val keystorePropertiesFile = rootProject.file("keystore.properties")
+val keystoreProperties = Properties()
+if (keystorePropertiesFile.exists()) {
+    keystoreProperties.load(keystorePropertiesFile.inputStream())
+}
+
 android {
+
+    signingConfigs {
+        if (keystorePropertiesFile.exists()) {
+            create("release") {
+                storeFile = rootProject.file(keystoreProperties["storeFile"] as String)
+                storePassword = keystoreProperties["storePassword"] as String
+                keyAlias = keystoreProperties["keyAlias"] as String
+                keyPassword = keystoreProperties["keyPassword"] as String
+            }
+        }
+    }
+
     namespace = "top.yeij.cyrene"
     compileSdk = 36
 
@@ -21,6 +41,9 @@ android {
 
     buildTypes {
         release {
+            if (keystorePropertiesFile.exists()) {
+                signingConfig = signingConfigs.getByName("release")
+            }
             isMinifyEnabled = true
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),