fix(deps): resolve 7 npm audit vulnerabilities for OpenSSF scorecard (#335)

- Add npm overrides for serialize-javascript (^7.0.3) and yauzl (^3.2.1)
  to fix GHSA-5c6j-r48x-rmvq and GHSA-gmq8-994r-jv83 respectively
- Regenerate lockfile to pick up fixes for flatted (<3.4.0) and
  undici (<7.24.0) covering 4 additional advisories
- All are devDependencies transitive deps; no impact on shipped extension

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Model-Raw: claude-opus-4-6

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: nullvariant