fix: update vulnerable dependencies

- next: ^15.5.14 -> ^15.5.15 (GHSA-q4gf-8mx6-v5v3)
- file-type: override to ^21.3.1 (CVE-2026-31808)
- lodash: override to ^4.18.0 (CVE-2026-4800)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sahansera