fix: update npm and fix token escaping in release workflow

[nastassiafulconis]

Problem

The release workflow had two issues:

1. Older npm version that may not support newer authentication features
2. Token variable was escaped in .npmrc, writing literal ${NPM_TOKEN} instead of the actual token value

Changes

• ✅ Added npm update step to ensure npm 11.5.1+ is installed
• ✅ Fixed token escaping by removing backslash in echo command (line 40)

Root Cause

The escaped variable \${NPM_TOKEN} was writing the literal string instead of expanding to the actual token value, which meant npm never got authenticated properly.

Testing

Once merged, the release workflow should properly:

1. Use latest npm with all authentication features
2. Write the actual token to .npmrc
3. Successfully publish to npm registry