Fix: Update npm username regex to support underscores and dots

Author: NandkishorJadoun

shared/schemas/user.ts

@@ -1,6 +1,6 @@
 import * as v from 'valibot'
 
-const NPM_USERNAME_RE = /^[a-z0-9]([a-z0-9-]*[a-z0-9])?$/i
+const NPM_USERNAME_RE = /^[a-z0-9]([a-z0-9-_.]*[a-z0-9])?$/i
 const NPM_USERNAME_MAX_LENGTH = 50
 
 /**