core-locale: shared per-app language plumbing (AppLanguage)

Android-library module, drawn from the byte-identical AppLanguage in Agendula
and Calendula: read the shipped languages from res/xml/locales_config.xml,
get/set the applied language via AppCompatDelegate, and render each language's
autonym. The locales_config resource id is now a parameter, so the module is
app-agnostic. appcompat only, no Compose.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

settings.gradle.kts

@@ -33,6 +33,7 @@ rootProject.name = "floret-kit"
 
 include(":core-time")
 include(":core-reminders")
+include(":core-locale")
 include(":core-crash")
 include(":identity")
 include(":components")