security: implement CRITICAL and MEDIUM security fixes with environment profiles

This commit addresses all CRITICAL and MEDIUM security vulnerabilities
identified in the security audit with environment-aware configuration.

## Docker Compose Profiles

- Added docker-compose.dev.yml for development (relaxed security)
- Added docker-compose.prod.yml for production (strict security)
- Environment-specific configurations for rate limiting, CSRF, logging

## CRITICAL Fixes (P0)

1. Fixed insecure random number generation
   - Replaced Math.random() with crypto.randomBytes() for verification codes
   - Now cryptographically secure

2. Implemented rate limiting
   - express-rate-limit for all endpoints
   - Strict limits on auth endpoints (5 attempts in dev=off, prod=5)
   - Email endpoint limits (20 in dev, 3 in prod)
   - API-wide rate limiting

3. Added request body size limits
   - Development: 50MB (for testing)
   - Production: 10KB (security)

4. Fixed user enumeration vulnerability
   - Generic error message for registration
   - No disclosure of which field exists

5. Added security headers
   - helmet.js with CSP, HSTS, XSS protection
   - No-sniff, hide powered-by headers

## MEDIUM Fixes (P1)

6. Strengthened password policy
   - Environment-aware validation (8+ chars)
   - Production: requires uppercase, lowercase, number
   - Development: relaxed for testing

7. Enhanced input validation
   - Validation for all auth endpoints
   - WSDC ID validation (numeric, max 10 digits)
   - Name validation (safe characters only)
   - Email normalization

8. Added input sanitization
   - DOMPurify for XSS prevention
   - Sanitize all user inputs in emails
   - Timing-safe string comparison for tokens

9. Improved error handling
   - Generic errors in production
   - Detailed errors only in development
   - Proper error logging

10. Enhanced CORS configuration
    - Whitelist-based origin validation
    - Environment-specific allowed origins
    - Credentials support

## New Files

- backend/src/config/security.js - Environment-aware security config
- backend/src/middleware/rateLimiter.js - Rate limiting middleware
- backend/src/utils/sanitize.js - Input sanitization utilities
- backend/.env.example - Development environment template
- backend/.env.production.example - Production environment template
- docker-compose.dev.yml - Development overrides
- docker-compose.prod.yml - Production configuration
- docs/DEPLOYMENT.md - Complete deployment guide
- docs/SECURITY_AUDIT.md - Full security audit report
- .gitignore - Updated to exclude .env files

## Dependencies Added

- helmet (^8.1.0) - Security headers
- express-rate-limit (^8.2.1) - Rate limiting
- dompurify (^3.3.0) - XSS prevention
- jsdom (^27.2.0) - DOM manipulation for sanitization

## Testing

- ✅ Password validation works (weak passwords rejected)
- ✅ User enumeration fixed (generic error messages)
- ✅ WSDC lookup functional
- ✅ Registration flow working
- ✅ Rate limiting active (environment-aware)
- ✅ Security headers present

## Usage

Development:
  docker compose -f docker-compose.yml -f docker-compose.dev.yml up

Production:
  docker compose -f docker-compose.yml -f docker-compose.prod.yml up

See docs/DEPLOYMENT.md for detailed instructions.

backend/.env.production.example

@@ -0,0 +1,69 @@
+# Production Environment Configuration
+# NEVER commit this file with real values!
+# Use environment variables or secrets manager in production
+
+# Server
+NODE_ENV=production
+PORT=3000
+
+# CORS - Your production domains
+CORS_ORIGIN=https://spotlight.cam,https://www.spotlight.cam
+
+# Database - Use managed database or strong credentials
+# NEVER use default passwords in production!
+DATABASE_URL=postgresql://prod_user:STRONG_PASSWORD_HERE@db:5432/spotlightcam_prod
+
+# JWT - CRITICAL: Generate strong secrets
+# Generate with: openssl rand -base64 64
+JWT_SECRET=CHANGE_THIS_TO_RANDOM_64_CHAR_STRING
+JWT_EXPIRES_IN=24h
+
+# AWS SES - Production credentials
+# BEST PRACTICE: Use IAM roles instead of access keys
+AWS_REGION=us-east-1
+AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
+AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+SES_FROM_EMAIL=noreply@spotlight.cam
+SES_FROM_NAME=spotlight.cam
+
+# Email Settings
+FRONTEND_URL=https://spotlight.cam
+VERIFICATION_TOKEN_EXPIRY=24h
+
+# Security Settings - Production (strict)
+RATE_LIMIT_ENABLED=true
+RATE_LIMIT_WINDOW_MS=900000
+RATE_LIMIT_MAX=100
+RATE_LIMIT_AUTH_MAX=5
+RATE_LIMIT_EMAIL_MAX=3
+ENABLE_CSRF=true
+BODY_SIZE_LIMIT=10kb
+LOG_LEVEL=warn
+
+# Password Policy - Enforced in production
+PASSWORD_MIN_LENGTH=8
+PASSWORD_REQUIRE_UPPERCASE=true
+PASSWORD_REQUIRE_LOWERCASE=true
+PASSWORD_REQUIRE_NUMBER=true
+PASSWORD_REQUIRE_SPECIAL=false
+
+# Account Lockout - Enabled in production
+ENABLE_ACCOUNT_LOCKOUT=true
+MAX_LOGIN_ATTEMPTS=5
+LOCKOUT_DURATION_MINUTES=15
+
+# Database Connection Pool
+DB_POOL_MIN=2
+DB_POOL_MAX=10
+
+# Monitoring (optional)
+SENTRY_DSN=
+NEW_RELIC_LICENSE_KEY=
+
+# IMPORTANT SECURITY NOTES:
+# 1. Generate JWT_SECRET with: openssl rand -base64 64
+# 2. Use AWS IAM roles instead of access keys when possible
+# 3. Use environment variables or secrets manager (AWS Secrets Manager, HashiCorp Vault)
+# 4. Never commit .env files to version control
+# 5. Rotate all secrets regularly (every 90 days)
+# 6. Use strong database passwords (20+ characters, mixed case, numbers, symbols)