docs: add production environment guide

[AlbertSong1024]

Summary

This PR adds a comprehensive guide for using kubectl-ai safely in production environments.

Changes

• Added docs/production-guide.md with detailed production deployment guidance

Guide Contents

1. Security Best Practices

   • Least privilege service account setup
   • Sandbox environment testing
   • Command approval configuration
   • Enterprise LLM provider integration (Vertex AI, Azure OpenAI)

2. Operational Guidelines

   • Audit logging setup and configuration
   • Resource quota implementation
   • Network policy configuration

3. Monitoring and Alerting

   • Command execution monitoring
   • Prometheus alert rules for suspicious activities

4. Production Deployment Checklist

   • Complete checklist for production readiness
   • Step-by-step deployment guide

5. Troubleshooting

   • Common issues and solutions
   • Permission debugging
   • LLM provider connection testing

Example Configurations

The guide includes working examples for:

• Service account creation with RBAC
• Network policy implementation
• Resource quota setup
• Multi-provider LLM configuration

Related

Closes #500

Testing

• Verified all code examples are syntactically correct
• Checked links to official documentation
• Ensured consistent formatting with existing docs

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