Adding projects to a workspace took one folder at a time. Choosing a folder that is not itself a project now scans below it, up to four levels and a shared entry budget, without following symlinks or descending into a project and skipping dependency, output and hidden directories. The projects found appear in a checklist with linked ones disabled; a folder with none is added as before. The scan is cancellable and runs in both the create and manage dialogs.
Fixes#2102
Workspaces open several local project folders in one IDE session (File › New / Open / Manage Workspace…, or Attach when opening a project, which creates a workspace automatically for a plain project window). Member folders are the Project view roots and take part in indexing, Find in Files, Git, language servers, run configurations and builds; agent tasks choose which member they work in. Window › Merge All Project Windows groups project windows into one window with project tabs (switch, reorder, close, move to a new window), restored on reopen.
Closes#241Closes#198Closes#286