Track protocol stream open/close count in metrics

[wemeetagain]

Current metrics include libp2p_protocol_streams_total which is a guage of current open protocol streams (with a single label protocol=direction + " " + protocol)

It would be more useful to have separate counter metrics for stream open and stream close. This would allow us to compute total (open - close) as well as rates of open and close.

[Hany-Almnaem]

Hi @wemeetagain @achingbrain ,
I'd like to work on this issue. I've analyzed the current metrics implementation and have a clear understanding of what needs to be implemented.

My approach:

• Add separate counter metrics for libp2p_protocol_streams_opened_total and libp2p_protocol_streams_closed_total

• Integrate tracking at stream lifecycle points in the connection manager

• Maintain the existing gauge metric for backward compatibility

• Use the same label format (direction + " " + protocol) for consistency

Please let me know if this approach sounds good, I can have a PR ready within a few days.