Feature request: Support pinned chats in the Codex VS Code extension

Summary

Please add support for pinning Codex chats/threads in the VS Code extension, matching the pinned-chat behavior already available in the Codex desktop app.

What problem are you seeing?

The VS Code extension currently makes it harder to keep important or long-running Codex threads easy to find. When working across multiple repositories, tasks, or VS Code windows, useful threads can get pushed down by newer activity and become awkward to return to.

In the Codex desktop app, pinned chats provide a simple way to keep important sessions visible. The VS Code extension would benefit from the same workflow, especially because the extension is often used inside active coding projects where certain threads remain relevant for days or weeks.

Existing model in Codex Desktop

This request is not asking for a brand-new session-management concept from scratch. Codex Desktop already has the desired product model:

• Chats/threads can be pinned and unpinned.
• Pinned chats remain easy to find across normal history churn.
• Pinned state persists.
• Pinned chats are visually prioritized in the sidebar.

The core ask is extension parity: expose the existing pinned-chat behavior in the VS Code extension history/session UI. If the underlying thread/session model already stores pinned state, the VS Code extension may be able to reuse that same state and add the missing UI affordance.

What would you like to see?

Add a pin/unpin action for Codex chats or threads in the VS Code extension.

Expected behavior:

• Users can pin and unpin chats from the VS Code extension history/session UI.
• Pinned chats remain visible above ordinary recent chats, similar to the Codex desktop app.
• Pinned state persists across VS Code restarts.
• Pinned state should sync or at least stay consistent with Codex desktop when both surfaces show the same thread.
• The UI should make pinned chats visually recognizable, for example with a pin icon.

MVP scope

This does not need to include custom sorting, tabs, search, project grouping, pagination changes, or a full history redesign. A first useful version would simply expose pin/unpin for VS Code extension threads and show pinned threads above ordinary recent threads.

Acceptance criteria

• Each thread in the VS Code extension history/session UI has a pin/unpin action.
• Pinned threads appear above unpinned recent threads.
• Pinned state persists across VS Code restarts.
• If the desktop app and VS Code extension share the same thread state, pinned state is consistent between them.
• Unpinning a thread returns it to normal recency sorting.

Why this matters

Pinned chats are useful for ongoing work such as:

• long-running implementation threads
• review/debugging sessions that need to be revisited
• planning threads for a project
• important project context that should not be buried by newer sessions

This is especially important in VS Code, where users often keep several parallel coding threads active and need fast access without scanning the full history list.

Why this may be high leverage

Because Codex Desktop already supports pinned chats, this may be more of a surface-parity feature than a new product concept. Pinning also gives users a lightweight way to keep important long-running coding sessions accessible while broader session-history improvements like #26982 are still being considered.

Related issues

• #24594 asks for keeping the session list visible alongside the active VS Code chat, but explicitly lists pinned sessions as a non-goal.
• #26762 asks for pinning and custom sorting in the Codex app project sidebar, but is not specifically about the VS Code extension.
• #26982 asks for grouping Codex VS Code thread history by project/workspace, which is related session-history organization work.

This request is specifically for pinned chats/threads in the Codex VS Code extension.