Add .npmrc to .gitignore to fix publish workflow

The NPM publish workflow creates a .npmrc file for authentication,
which was causing the 'auto shipit' command to fail with "Working
directory is not clean" error. Adding .npmrc to .gitignore resolves
this issue.

Author: claude

.gitignore

@@ -35,6 +35,9 @@ node_modules/
 # Lock files (use yarn.lock only)
 package-lock.json
 
+# NPM config (created by CI for authentication)
+.npmrc
+
 # OSX
 .DS_Store
 .env