Project folders in the web app (already in the desktop app)

[mARTin-B78]

The desktop app lets you point a project at a folder that already exists on your machine, so agents work in that directory instead of a fresh clone. The web app has no equivalent. In the create-project dialog the local-directory option depends on the desktop directory picker, so people who run Multica in the browser, for example on a self-hosted server with a separate runtime machine, can't use it.

I use Multica self-hosted, mostly through the browser, and I really wanted this. So I've built it on my fork, to see whether it fits:

In the web create-project dialog you choose a runtime computer and type the absolute path of the folder on it. A browser can't browse a remote filesystem, so the daemon checks the path when a run starts.
You can pick how agents use the directory. Direct mode uses that checkout as it is, without cloning, and allows one run at a time.
You can attach a folder to an existing project after it's been created, and combine it with repositories on the same project.
Workspace settings has a place to configure the project locations per runtime.
It reuses the local-directory project resource the desktop app already has. The main difference is where the path comes from: a typed path plus a chosen runtime instead of a native picker.

Some open questions:

Is this something you'd want in the web app, or is the desktop-only behaviour deliberate (for example for security)?
If you're open to it, is a typed path plus daemon-side validation acceptable, or would you rather have another way to choose the folder?
Should "direct" mode be exposed in the web at all?
I'm happy to rebase onto current main, clean it up, and open a PR if there's interest.