One version number between a blank screen and weather

The app booted, then rendered nothing — blank screen, no errors, just Cannot read properties of undefined (reading 'S') buried in the Three.js internals. Classic version mismatch: @react-three/[email protected] was installed but @react-three/[email protected] expected fiber v8. The initial cleanup had migrated the env vars and Tailwind, but left the peer dep conflict untouched because npm install --legacy-peer-deps masks it. One line in package.json — downgrading fiber from ^9 to ^8.18.0 — and the 3D cloud shaders, precipitation particles, drag-to-reorder cards, and Studio mode all came alive at once. Zero console errors. The Gemini AI prompt bar, the exploded-layer inspector, the dark/light toggle — everything worked. 1,910 lines of TypeScript across 11 source files, 553 of them in WeatherCard.tsx alone, and the only thing standing between "broken export" and "portfolio piece" was a caret in a version range.