🟡 HIGH: Implement application logging

[GitAddRemote]

Problem

Minimal logging - only EventConsumer has a logger

Solution

Add SLF4J loggers to all services and controllers:

• UserService, JwtService, LoginRateLimiter
• All controllers
• Security event logging
• Add CorrelationIdFilter for request tracing

Acceptance Criteria

• All services have loggers
• Security events logged
• Correlation IDs in logs
• No sensitive data in logs

Priority

🟡 High - Critical for troubleshooting