A Refactor of signing config to simplify keystore handling

The `app/build.gradle.kts` file has been updated to simplify the release signing configuration.

The previous implementation included logic to decode a base64 encoded keystore from an environment variable (`KEY_STORE_FILE`) and write it to a temporary file. This logic, along with the associated `Base64` import, has been removed.

The new configuration now directly references the `mLauncher.jks` file within the `app/` directory and retrieves the keystore password, key alias, and key password from their respective environment variables. This change assumes the keystore file is present at build time, streamlining the signing process within the Gradle script.

Author: CreativeCodeCat

app/build.gradle.kts

@@ -1,5 +1,3 @@
-import java.util.Base64
-
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
@@ -72,43 +70,18 @@ android {
     }
 
     signingConfigs {
-        val keystoreB64: String =
-            System.getenv("KEY_STORE_FILE") ?: throw GradleException("KEY_STORE_FILE not set.")
-        val keystorePassword: String =
-            System.getenv("KEY_STORE_PASSWORD") ?: throw GradleException("KEY_STORE_PASSWORD not set")
-        val keyAlias: String =
-            System.getenv("KEY_ALIAS") ?: throw GradleException("KEY_ALIAS not set")
-        val keyPassword: String =
-            System.getenv("KEY_PASSWORD") ?: throw GradleException("KEY_PASSWORD not set")
-
-        // Use file helper to ensure correct path
-        val localKeystore = rootProject.file("app/mLauncher.jks")
-        val ciKeystore = layout.buildDirectory.file("temp-keystore.jks").get().asFile
-
-        val keystoreFile = when {
-            localKeystore.exists() -> localKeystore
-            else -> ciKeystore
-        }
-
-        if (!keystoreFile.exists()) {
-            keystoreFile.parentFile.mkdirs()
-
-            val bytes = Base64.getDecoder().decode(keystoreB64)
-
-            if (bytes.size < 1024) {
-                throw GradleException("Decoded keystore is too small (${bytes.size} bytes)")
-            }
-
-            keystoreFile.writeBytes(bytes)
-        }
+        create("release") {
+            val keystoreFile = rootProject.file("app/mLauncher.jks")
 
-        println("Using keystore: ${keystoreFile.absolutePath} (${keystoreFile.length()} bytes)")
+            println("Using keystore: ${keystoreFile.absolutePath} (${keystoreFile.length()} bytes)")
 
-        create("release") {
             storeFile = keystoreFile
-            storePassword = keystorePassword
-            this.keyAlias = keyAlias
-            this.keyPassword = keyPassword
+            storePassword = System.getenv("KEY_STORE_PASSWORD")
+                ?: error("KEY_STORE_PASSWORD not set")
+            keyAlias = System.getenv("KEY_ALIAS")
+                ?: error("KEY_ALIAS not set")
+            keyPassword = System.getenv("KEY_PASSWORD")
+                ?: error("KEY_PASSWORD not set")
         }
     }