Add gig expiry worker error handling

[meshackyaro]

Description

GigExpiryWorker has memory leak - memory increases over time eventually causing OOM.

Component

Backend

Difficulty

🟡 Medium

Tasks

• Audit for event listener leaks
• Check database connection cleanup
• Profile memory usage
• Fix identified leaks
• Add memory monitoring

Acceptance Criteria

• Memory usage stable over time
• No OOM crashes
• Memory leaks fixed

Estimated Time

2-3 days