Realtime feed leaks sockets and listeners

Challenge summary

Route changes and filter changes keep adding listeners, so old listeners stay alive and still use old filter values.

What you'll practice

• Separate visible symptoms from the underlying cause.
• Prioritize the highest-signal investigation before changing code.
• Choose a durable fix and define a focused regression guard.

What Premium unlocks

Premium unlocks the staged investigation, evidence-based scoring, root-cause walkthrough, and regression-guard discussion.