Initialize the browser i18next instance with lazy per-locale catalog loading,
localStorage->navigator->htmlTag detection, script-aware zh fallback, and the
shared @fusion/i18n config. Catalogs are synced from @fusion/i18n into a
gitignored app/locales/ (predev/prebuild) and imported app-relative so Vite
emits one chunk per locale/namespace (verified: 15 chunks, none inlined into
the main bundle). First paint is gated on i18nReady to avoid raw-key flashes;
<I18nextProvider> wraps the App provider stack; vendor-i18n manualChunk added.
A build-assertion script (verify:locale-chunks) guards the KTD3a splitting
invariant. Fallback/namespace behavior is covered by @fusion/i18n config tests;
the live instance is verified via the build assertion rather than a unit test
(the dynamic catalog backend is impractical to exercise in vitest).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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