chore: add .npmrc to gitignore

Prevent accidental commit of npm auth tokens.

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

Author: rrodrigu3z

.gitignore

@@ -14,6 +14,7 @@ coverage/
 # Environment
 .env
 .env.local
+.npmrc
 
 # IDE
 .vscode/