Localize remaining hardcoded UI strings and persist language preference

Replaces the last hardcoded English strings (initial-scene modals, game
menu save status messages) with locale-loaded text, adds a shared
LOCALE_LIST so the settings dropdown and locale manager stay in sync,
and persists the chosen language into savemeta_t across all platforms.
Also fixes two message buffers that were too small for their longest
translations.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/dusklinux/save/savelinux.c

@@ -120,6 +120,9 @@ errorret_t saveMetaLoadLinux(savemeta_t *out) {
   out->deadzone = saveJsonReadFloatLinux(
     root, "deadzone", SAVE_META_DEADZONE_DEFAULT
   );
+  out->language = saveJsonReadUInt8Linux(
+    root, "language", SAVE_META_LANGUAGE_DEFAULT
+  );
   out->exists = true;
 
   yyjson_doc_free(doc);
@@ -136,6 +139,7 @@ errorret_t saveMetaWriteLinux(savemeta_t *meta) {
   errorChain(saveJsonWriterInitLinux(&writer));
   saveJsonWriterAddUInt32Linux(&writer, "version", meta->version);
   saveJsonWriterAddFloatLinux(&writer, "deadzone", meta->deadzone);
+  saveJsonWriterAddUInt8Linux(&writer, "language", meta->language);
 
   errorret_t ret = saveJsonWriterSaveLinux(&writer, path);
   saveJsonWriterDisposeLinux(&writer);