CI's npm ci (strict peer resolution) rejected the TypeScript 5.9 bump
from the Next.js migration: react-scripts still declares typescript
^3.2.1||^4 as a peer. Local `npm install` didn't catch this -- it
resolves peer conflicts leniently by default; only `npm ci` enforces
them. react-scripts is kept solely as the Jest test runner now (it
doesn't type-check), so relaxing this one peer constraint is safe.
cesnimda