feat: allow manual directory path entry when adding projects

[eggfriedrice24]

Problem

On Wayland (Linux), GTK file picker dialogs have known issues that can make folder selection unreliable or broken entirely. This makes adding projects through the native file picker frustrating or impossible for some users.

Right now I literally can't select folders to test stuff because the GTK picker just doesn't cooperate on Wayland.

Proposal

Bring back the ability to manually type/paste a directory path when adding a project, as an alternative to the native file picker dialog. A text input alongside the existing "Browse" button would be great.

Why

• GTK file picker on Wayland is buggy for folder selection in Electron apps
• Power users often prefer pasting paths directly anyway
• Low effort fallback that unblocks users on broken desktop environments

cc @juliusmarminge @t3dotgg

[eggfriedrice24]

Happy to work on a PR for this. If you have a better UX in mind than how it was before let me know. Could also add tab autocomplete for the path input, server returns matching directories for a partial path and Tab fills in the completion, with a dropdown when there are multiple matches. Would feel pretty natural.

[eggfriedrice24]

This is kind of high priority for me since it completely blocks adding projects on Wayland right now. Can't really test or contribute much without it.