chore: npm audit fix — patch vite, dompurify, esbuild, brace-expansion

Resolves high-severity vite CVEs (GHSA-v6wh-96g9-6wx3, GHSA-fx2h-pf6j-xcff)
and moderate/low issues in dompurify, esbuild, brace-expansion.
Remaining 3 low-severity items (cookie in @sveltejs/kit) require a
breaking downgrade and are left as-is.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dani-polani