[nicoloboschi]

Summary

Internationalizes the control plane UI across 8 locales (en, es, fr, de, pt, ja, ko, zh) using next-intl. English keeps no prefix; other locales live under /{locale}/…. Adds a Globe language switcher in the navbar and login page.

Highlights

• Routing. Pages move under the [locale] segment. The existing auth middleware composes with createIntlMiddleware and strips the locale prefix before applying public-route rules. The matcher uses an explicit file-extension allowlist so bank IDs with dots (e.g. SX.Products.GovComply.Build) still hit the locale rewrite.
• Catalogs. Eight JSON catalogs in src/messages/, ~1100 keys each, covering bank navigation, all view panels (data, documents, entities, mental-models, think, recall debug, webhooks, audit logs), bank-config + profile + stats + operations, all detail modals, the graph/constellation, and the Add Document dialog. ICU plurals used for counts ({count, plural, one {…} other {…}}).
• Provider plumbing. [locale]/layout.tsx wraps children with NextIntlClientProvider alongside the existing ThemeProvider / FeaturesProvider / BankProvider. Root layout.tsx becomes a minimal shell.
• Locale parity test (src/messages/messages.test.ts, runs under npm test). Asserts (1) every declared locale has a JSON on disk and vice versa, (2) every locale has the exact same key set as en, (3) no leaf is empty.
• Static finder for hardcoded strings (scripts/find-untranslated.ts, exposed as npm run i18n:check). Walks the TSX AST under src/components and src/app, flags JSX text + human-facing JSX attributes (placeholder, title, aria-label, alt, label, description, tooltip), skipping anything already inside a t(...) / t.rich(...) / useTranslations(...) call expression. Skips identifiers, URLs, HTML entities, env vars, JSON sample placeholders, formulas, and pure comma-separated token lists.
• CI wiring. Both build-control-plane and the equivalent step in the build-hindsight-all job now run npm run i18n:check after npm test. Future drift in translations or untranslated strings fails the build.

Test plan

• npm run --workspace=hindsight-control-plane test — 49/49 (33 base + 16 locale-parity)
• npm run --workspace=hindsight-control-plane i18n:check — exits 0
• npx tsc --noEmit — clean
• Dev server smoke test: /, /dashboard, /es/login, /fr/banks/<id>, /ja/banks/<id> all render correctly; language switcher persists via NEXT_LOCALE cookie; /api/* skips i18n rewrites.

Notes

• next build fails on _global-error prerender (useContext null) — this reproduces on main and is unrelated to the port.