Plan 79 A1/A2/A4 + B1/B2.
Delivery deliberately avoids the usual http-backend fetch. `en` is bundled;
other locales are dynamic imports Vite emits as chunks from the app's own
static origin. The sign-in and setup screens render before any API call
succeeds, so a fetched locale either flashes English or -- when the backend
is the thing that is broken -- never arrives, on the one screen whose job is
to say so. It also keeps air-gapped and subpath installs working with no
second path to 404.
Precedence (user row -> localStorage -> panel default -> navigator -> en)
mirrors ThemeContext's, including the split provider: LocaleProvider sits
outermost so a toast raised during theme init is already translatable, and
LocaleSync bridges auth state down, exactly as ThemeSync does.
users.language is nullable on purpose -- "follow the panel default" is a
different state from an explicit choice of English, so existing rows are not
backfilled. The backend restates the supported list to validate writes; a
parity test fails the build if it drifts from the frontend manifest, which
stays canonical.
Two bugs the tests caught, both real rather than test artifacts:
- normalize_language('ES') returned None. The shape gate was case-sensitive,
so two of the three forms browsers actually send were rejected.
- PUT /me is throttled 3/minute for credential edits, and language rides the
same route. Switching language three times returned 429 -- and because the
client applies the change locally first, the preference silently failed to
persist and reverted on the next sign-in elsewhere, defeating the column.
Cosmetic-only payloads are now exempt from that limit; credential edits
stay throttled (proved both ways) and the app-wide 100/minute still holds.
eslint moves to ecmaVersion 'latest' because import attributes are ES2025 and
Node's test runner requires them for the manifest imports.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Juan Denis