Add admin user initialization script

Create init_admin.py script to properly initialize the admin user
with correct password hash for "admin123".

Usage:
  python init_admin.py

This script:
- Creates admin user if it doesn't exist
- Uses proper bcrypt password hashing
- Stores user data in data/users.yaml (gitignored)
- Provides clear feedback about user creation

Credentials created:
- Username: admin
- Password: admin123
- Role: administrator

Note: data/users.yaml is gitignored (correct for user data), so
admin user must be initialized on each installation.

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

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

init_admin.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+"""Initialize admin user for Reklamator"""
+import os
+from app import create_app
+from app.models.user import User
+
+
+def init_admin():
+    """Create initial admin user if it doesn't exist"""
+    app = create_app('development')
+
+    with app.app_context():
+        # Check if admin user already exists
+        existing_admin = User.get_by_username('admin')
+
+        if existing_admin:
+            print("✓ Admin user already exists")
+            print(f"  Username: admin")
+            print(f"  Email: {existing_admin.email}")
+            return
+
+        # Create admin user
+        admin = User.create(
+            username='admin',
+            email='admin@reklamator.local',
+            password='admin123',
+            role='administrator',
+            product_ids=[]
+        )
+
+        print("✓ Admin user created successfully!")
+        print(f"  Username: admin")
+        print(f"  Password: admin123")
+        print(f"  Email: {admin.email}")
+        print(f"  User ID: {admin.user_id}")
+        print("")
+        print("⚠️  IMPORTANT: Change the password in production!")
+
+
+if __name__ == '__main__':
+    init_admin()