245 keys had accumulated in en/es only (trustUi, labOptions, cordnUi, socialUi,
walletUi, marketTerms, …), leaving every other locale at 97%. Backfilled 245x20 =
4,900 strings into src/i18n/<lang>/drift.ts and merged them through a new shared
src/i18n/deepMerge.ts — a shallow ...drift spread would clobber existing
namespaces, so index.ts deep-merges instead. Verified: check-i18n all 20 at 100%,
tsc + eslint clean.
