fix: update vulnerable dependencies

[dipankarmaikap]

Summary

• update Next.js and related dependencies to resolve the reported Aikido vulnerabilities
• update Storyblok, React, Netlify, and lint dependencies
• use Next.js native flat ESLint config and correct the package name to blueprint-core-nextjs

Verification

• npm audit --audit-level=low reports 0 vulnerabilities
• npm ci --ignore-scripts passes
• npm run lint passes
• npm run build passes

The build emits the existing informational warning about the missing Storyblok access token.