Allow users to configure how many conversations appear in Recents

What variant of Codex are you using?

Codex Desktop / App

What feature would you like to see?

Please let users choose how many conversations are shown in the Recents section of the sidebar.

A useful setting could offer values such as 5, 10, 20, 50, or All, with a Show more action for anything beyond the chosen initial count.

I use projectless conversations for recurring tasks such as daily briefs. These create many short-lived threads, so showing 50 recent conversations makes the Recents section very long and pushes my Projects too far down the sidebar. Moving Recents below Projects only reverses the problem: Recents then becomes too far down to reach conveniently.

The visible Recents count should be a presentation preference, separate from conversation retention and loading. Choosing a small number must not hide conversations from search, remove history, or limit the full paginated history available inside each project.

Expected behavior

• Users can configure the number of conversations initially visible under Recents.
• A small selection such as 5 or 10 keeps Projects easy to reach.
• Older conversations remain available through search and a Show more / full-history view.
• Project conversation history continues to load independently of the global Recents display count.

Related issue

This is related to #25761, but it addresses a different need. That issue asks for complete access to older project conversations beyond the global recent-50 window. This request asks for control over how many recent conversations are visibly expanded in the sidebar, without reducing access to any saved history.

No files, tests, or entry points are named. Start by locating the Codex Desktop Recents sidebar, its settings UI, and the code that loads global and project conversation history; confirm how the visible count is stored and applied. Done means a configurable initial Recents count, Show more or full-history access, and unchanged search and project history behavior.