Allow opening the FS root dir as a remote project (#30190)

### Todo

* [x] Allow opening `ssh://username@host:/` from the CLI
* [x] Allow selecting `/` in the `open path` picker
* [x] Allow selecting the home directory in the `open path` picker

Release Notes:

- Changed the initial state of the SSH project picker to show the full
path to your home directory on the remote machine, instead of `~`.
- Added the ability to open `/` as a project folder over SSH

---------

Co-authored-by: Agus Zubiaga <hi@aguz.me>

crates/project_panel/src/project_panel.rs

@@ -2855,13 +2855,7 @@ impl ProjectPanel {
                 }
                 let worktree_abs_path = worktree.read(cx).abs_path();
                 let (depth, path) = if Some(entry.entry) == worktree.read(cx).root_entry() {
-                    let Some(path_name) = worktree_abs_path
-                        .file_name()
-                        .with_context(|| {
-                            format!("Worktree abs path has no file name, root entry: {entry:?}")
-                        })
-                        .log_err()
-                    else {
+                    let Some(path_name) = worktree_abs_path.file_name() else {
                         continue;
                     };
                     let path = ArcCow::Borrowed(Path::new(path_name));