chore(deps): update eslint to fix flatted vulnerability

[Piyush-85]

SEC-16542 Vulnerability Fix

Issue

Snyk vulnerability SEC-16542 in flatted package (versions 3.3.1, 3.3.3)

Root Cause

• Vulnerable versions locked in pnpm-lock.yaml via: eslint → file-entry-cache → flat-cache@4.0.1 → flatted@^3.2.9
• Lockfile resolved to vulnerable 3.3.x instead of fixed 3.4.2

Solution

Updated ESLint to 9.39.4 across all packages to force re-resolution of flatted to 3.4.2

Changes

Package Updates

Package	ESLint Version Change
Root	9.20.0 → 9.39.4
e2e/test-app	8.x → 9.39.4
examples/with-next-intl	Added 9.39.4
examples/with-shadcn	9.13.0 → 9.39.4
examples/with-mrrt	9.13.0 → 9.39.4

TypeScript Fixes (with-next-intl)

• Replaced as any with as (typeof routing.locales)[number] in:
  • app/[locale]/layout.tsx:15
  • src/i18n/request.ts:10

Verification

• ✅ All lockfiles show flatted@3.4.2
• ✅ Build successful (root + all examples)
• ✅ Lint successful (root + all examples)
• ✅ No dependency overrides needed

Result

SEC-16542 vulnerability resolved across entire repository with clean dependency resolution.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.48%. Comparing base (6b272d1) to head (7568904).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2575   +/-   ##
=======================================
  Coverage   90.48%   90.48%           
=======================================
  Files          53       53           
  Lines        6684     6684           
  Branches     1403     1403           
=======================================
  Hits         6048     6048           
  Misses        624      624           
  Partials       12       12           

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