Keep Xiaomi CS2 control notifications from stopping media

[RuiFG]

Summary

• keep Xiaomi MISS/CS2 media running when unsolicited control notifications are not consumed after login
• discard the oldest command notification when the bounded command queue is full
• leave media queues strict so media corruption is not hidden

Root cause

The Xiaomi CS2 connection has a command channel with a bounded queue. After login, some cameras continue to send unsolicited control notifications, but there is no long-running command consumer. Once the queue fills, Push returns pop buffer is full, the worker exits, and the entire media connection restarts. This creates a repeatable multi-second video gap.

Validation

• go test ./pkg/xiaomi/miss/cs2 ./pkg/xiaomi/miss
• added coverage confirming media queues still fail when full and command queues retain the newest notification