fix: use correct bcrypt package in create-admin script

- Change from bcryptjs to bcrypt to match installed dependency
- Fixes "Cannot find module 'bcryptjs'" error when creating admin user

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/scripts/create-admin.js

@@ -8,7 +8,7 @@
  */
 
 require('dotenv').config();
-const bcrypt = require('bcryptjs');
+const bcrypt = require('bcrypt');
 const { db } = require('../src/database/db');
 const crypto = require('crypto');