Show Hidden Counts on Each Tab

What variant of Codex are you using?

App

What feature would you like to see?

As shown in the following screenshots, when we fold session items in a tab,
we can' find how many sessions are hidden until we open a folded tab.

Especially in the Pinned tab, this count info is necessary,
because we do not want to forget unpin items if pinned items exist.

<img width="142" height="56" alt="Image" src="https://github.com/user-attachments/assets/b19c87c9-02e9-4164-b8c3-6266f71eaf8e" />

<img width="147" height="22" alt="Image" src="https://github.com/user-attachments/assets/0934b35b-c5fd-4c61-98a4-af55f19397d7" />

Additional information

_No response_