TinyWorld i18n workflow

TinyWorld localizes its gameplay UI into English (en), French (fr), Simplified Chinese (zh), and Spanish (es). This skill is the repeatable process for keeping those translations complete and consistent. There is no external API: you (Codex) are the translator. The checker (npm run i18n:check) is the safety net.

Read docs/i18n.md first if you need the architecture. The short version:

• Locale dictionaries live in engine/i18n/{en,fr,es,zh}.js as flat key→string maps.
• en.js is authoritative. Every other locale must define exactly its key set.
• Static HTML uses data-i18n / data-i18n-title / data-i18n-tooltip / data-i18n-placeholder / data-i18n-aria-label attributes.
• JS uses the global t('key') (or tx('key', fallback) to keep a hard-coded English default). Tool/group/variant labels are localized by a single mutation block near the top of engine/world/19-tools-toolbar.js.
• Language switching is reload-on-switch (persist + location.reload()), so every surface re-renders correctly at boot. Don't add live re-render wiring.