Enable per-app language preferences

This commit enables the automatic generation of per-app language preferences by configuring the Android Gradle Plugin.

A `resources.properties` file is added to specify `en` as the `unqualifiedResLocale`, which serves as the default/fallback locale.

Additionally, `.kotlin` is added to `.gitignore` to exclude Kotlin build-related files.

app/build.gradle.kts

@@ -24,6 +24,11 @@ android {
         testInstrumentationRunner = "eu.darken.capod.HiltTestRunner"
     }
 
+    // Enable automatic per-app language preferences generation
+    androidResources {
+        generateLocaleConfig = true
+    }
+
     signingConfigs {
         val basePath = File(System.getProperty("user.home"), ".appconfig/${ProjectConfig.packageName}")
         create("releaseFoss") {

app/src/main/res/resources.properties

@@ -0,0 +1,4 @@
+# This file configures automatic per-app language preference support
+# It tells AGP to generate LocaleConfig automatically from available translations
+# The unqualifiedResLocale is the default/fallback locale (from res/values/strings.xml)
+unqualifiedResLocale=en