fix: use bcp47 locale codes for BuildConfig

Split locale lists to use Android resource qualifier format for
localeFilters and BCP 47 format for BuildConfig.LOCALES, fixing
Locale.forLanguageTag() compatibility in tests.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jvsena42

app/build.gradle.kts

@@ -37,9 +37,14 @@ val keystoreProperties by lazy {
     keystoreProperties
 }
 
-val locales = listOf(
+// Android resource qualifier format for androidResources.localeFilters
+val androidLocales = listOf(
     "en", "ar", "b+es+419", "ca", "cs", "de", "el", "es", "es-rES", "fr", "it", "nl", "pl", "pt", "pt-rBR", "ru"
 )
+// BCP 47 format for BuildConfig.LOCALES (used with Locale.forLanguageTag())
+val bcp47Locales = listOf(
+    "en", "ar", "es-419", "ca", "cs", "de", "el", "es", "es-ES", "fr", "it", "nl", "pl", "pt", "pt-BR", "ru"
+)
 val e2eBackendEnv = System.getenv("E2E_BACKEND") ?: "local"
 
 android {
@@ -58,7 +63,7 @@ android {
         buildConfigField("boolean", "E2E", System.getenv("E2E")?.toBoolean()?.toString() ?: "false")
         buildConfigField("String", "E2E_BACKEND", "\"$e2eBackendEnv\"")
         buildConfigField("boolean", "GEO", System.getenv("GEO")?.toBoolean()?.toString() ?: "true")
-        buildConfigField("String", "LOCALES", "\"${locales.joinToString(",")}\"")
+        buildConfigField("String", "LOCALES", "\"${bcp47Locales.joinToString(",")}\"")
     }
 
     flavorDimensions += "network"
@@ -148,7 +153,7 @@ android {
     }
     androidResources {
         @Suppress("UnstableApiUsage")
-        localeFilters.addAll(locales)
+        localeFilters.addAll(androidLocales)
         @Suppress("UnstableApiUsage")
         generateLocaleConfig = true
     }