Opt-in custom order for boring sidebar project folders (PR #33227)

[HarunRRayhan]

I'd like to ask whether this direction is OK. I built it because I need it, and the PR is up as #33227, but I don't have maintainer approval yet and your contributing guide asks for it.

The problem. With the boring sidebar, project folders follow agent activity, so they keep changing place. There is a Manual project order setting, but since #21039 removed the legacy sidebar's drag there is no way to change that order (#27062).

What the PR does.

• Adds a Customize project order switch under Boring sidebar in Settings → Labs. It only turns on the existing Manual setting, so nothing changes for anyone who leaves it off.
• With it on, Settings → Projects shows a numbered list you can drag, saved through the existing reorderProjects. Agent activity no longer moves the folders.
• Pinned projects still sort first, so the list marks them and adds one divider to show that limit.

There are no contract or server changes, and mobile is unchanged.

What I would like to know. Is an opt-in switch under the boring sidebar the right place for this, or would you rather have it somewhere else? Happy to change or cut whatever you would prefer.

Written with Claude Code.

[ivolkoff]

+1. I pin a few projects and want them in my own order. Since the legacy sidebar went away, I have no way to change the Manual order. The drag list in Settings → Projects from #33227 would solve this for me.

[chomamateusz]

+1. I use the same Manual order for more than folders: in my fork it also drives a row of project icons used as the project filter, so one order applies to both. Pinned-first with my own order inside each section, as in your PR, matches how I use it. Context: #36370