Allow manual reordering of pinned conversations

[ltz6]

Hi Daniel,

Thank you again for continuing to improve Litter.

I would like to request a feature for pinned conversations: it would be useful if pinned sessions could be manually reordered, similar to the official Codex app.

Current behavior:

• When selecting or opening a pinned conversation, it appears to move to the front/top of the pinned list.
• This makes it hard to keep a stable custom order for important conversations.
• If the user has several pinned sessions for different projects or contexts, the order changes just because one conversation was opened.

Requested behavior:

• Allow users to manually reorder pinned conversations, for example by dragging them or using a reorder action.
• Preserve that custom pinned order across app restarts.
• Opening or selecting a pinned conversation should not necessarily move it to the top unless the user explicitly chooses that behavior.

This would make pinned conversations more predictable and closer to the official Codex app experience.

Thanks.