I noticed a behavior in psmux that seems to deviate from both tmux conventions and the project's own README.

Describe the bug:
Currently, if no session exists, running psmux creates a session named default. If I detach from that session and run psmux again, it re-attaches to the default session instead of creating a new one.

Comparison with tmux:
In tmux, the behavior is different:

Running tmux for the first time creates session 0.
After detaching, running tmux again creates a new session named 1, and so on.

The README says:

# Start a new session
psmux

Is this an intentional design choice or a bug?