Create or update localization keys in the title's DEFAULT language. PARTIAL: only the keys you send are written, the rest of the table is untouched — people translate the same table, and replacing it wholesale would erase their work. Write ONLY the default language: other locales are filled by translators or by the dashboard's machine translation, and a string that exists only in a target language never appears in the coverage report. Keys are free-form; a dotted namespace ("shop.button.buy") keeps a large table readable.