[FEAT] Implement Security Middleware Stack

[JC-Coder]

Description

The current codebase lacks essential security middleware that are crucial for protecting our NestJS application against common web vulnerabilities. We need to implement several security measures to enhance our application's security posture.

Acceptance Criteria

• Implement Helmet middleware to set various HTTP headers for security
• Add compression middleware to optimize response payload size
• Configure CORS with strict options
• Set up security headers monitoring
• Add documentation for security configurations

Purpose

These security enhancements are critical because:

1. Helmet helps protect the app against well-known web vulnerabilities by setting appropriate HTTP headers
2. Compression reduces bandwidth usage and improves load times
3. Proper CORS configuration prevents unauthorized cross-origin requests

Requirements

• Install required packages:

  @nestjs/helmet
  compression

• Update main.ts to include new middleware
• Configure each security middleware with production-grade settings
• Implement monitoring for security-related events

Expected Outcome

After implementation, the application will have:

1. Secure HTTP headers set by Helmet:
   • XSS Protection
   • Content Security Policy
   • HSTS
   • Frame Options
   • and other security headers
2. Compressed responses for text-based content
3. Strict CORS policy
4. Enhanced security monitoring

Additional Context

Current security vulnerabilities this addresses:

1. Missing HTTP security headers
2. Potential for XSS attacks
3. No protection against DoS attacks
4. Uncompressed responses increasing bandwidth usage
5. Lack of request validation

Implementation Priority: HIGH
Estimated Implementation Time: 30 minutes
Impact: All API endpoints and application security