Strip legacy save/settings systems for a unified savemanager rewrite; split uielement list out of uielement.c

Removes the per-platform save/savestream/autosave implementations, the settings UI frames, and the autosave overlay, replacing them with a savemanager.c/h + savefile.h/savedevice.h scaffold to build the new save system on top of. Also separates the concrete UI_ELEMENTS registration into uielementlist.h/.c so uielement.c only holds the generic per-element lifecycle logic.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/duskdolphin/system/systemdolphin.h

@@ -47,5 +47,13 @@ int32_t systemGetAspectRatioDolphin(void);
  */
 int32_t systemGetLanguageDolphin(void);
 
+/**
+ * Returns the locale matching the system's configured language, falling
+ * back to LOCALE_DEFAULT if the system language has no matching locale.
+ *
+ * @return The current locale.
+ */
+const localeinfo_t * systemGetLocaleDolphin(void);
+
 // There's actually a tonne more things Wii can return, this is it for now
 // though.