chore: npm audit fix — resolve 10 of 14 vulnerabilities

Fixes critical handlebars AST injection, high-severity lodash-es code
injection, flatted prototype pollution, undici smuggling, and others.
Remaining 4 are mocha transitive deps (would require breaking downgrade).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Pedrovaleriolopez