fix(frontend): relax npm peer-dep resolution for react-scripts vs TS 5.9

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.

job-tracker-ui/.npmrc

@@ -0,0 +1,4 @@
+# react-scripts (kept only as the Jest test runner, see package.json) still declares a
+# typescript ^3.2.1||^4 peer constraint that's stale for our actual (Next.js-driven) TS 5.x --
+# it doesn't type-check via that peer path, so the conflict is safe to relax.
+legacy-peer-deps=true