i18n-Ready (bilingual by design, not by patch)

Design for the longest honest string; translate meaning, not words. English/Spanish is the worked pair; the method generalizes.

Make a locale contract before translating or resizing

Record a locale contract before resizing/translating:

Boundary	Required decision/evidence
locale/reader	concrete BCP 47 tag, fallback/owner, formality and regional vocabulary
content	whole-message keys, variables/plurals, protected legal/safety language
mechanics	formats and data source for date/time zone/number/currency/address/name
stress/direction	longest approved fixture by surface; current `dir`, RTL/bidi/logical-property path

Never invent locale, idiom, translation, or formality; pending source/approval is structural readiness only.