Adds enabled_languages on restaurants and translations JSONB on menu
categories/items. New /restaurants/:id/languages endpoints bulk-translate
the full menu via Gemini/GPT-4o-mini (reusing the ai-scanner dual-provider
pattern) when a language is enabled. New categories/items are auto-
translated in the background into any already-enabled languages.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
