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/src/project.rs

@@ -3904,11 +3904,7 @@ impl Project {
         })
     }
 
-    pub fn resolve_abs_path(
-        &self,
-        path: &str,
-        cx: &mut Context<Self>,
-    ) -> Task<Option<ResolvedPath>> {
+    pub fn resolve_abs_path(&self, path: &str, cx: &App) -> Task<Option<ResolvedPath>> {
         if self.is_local() {
             let expanded = PathBuf::from(shellexpand::tilde(&path).into_owned());
             let fs = self.fs.clone();
@@ -5124,6 +5120,13 @@ impl ResolvedPath {
         }
     }
 
+    pub fn into_abs_path(self) -> Option<PathBuf> {
+        match self {
+            Self::AbsPath { path, .. } => Some(path),
+            _ => None,
+        }
+    }
+
     pub fn project_path(&self) -> Option<&ProjectPath> {
         match self {
             Self::ProjectPath { project_path, .. } => Some(&project_path),

crates/project/src/worktree_store.rs

@@ -262,7 +262,7 @@ impl WorktreeStore {
         if abs_path.starts_with("/~") {
             abs_path = abs_path[1..].to_string();
         }
-        if abs_path.is_empty() || abs_path == "/" {
+        if abs_path.is_empty() {
             abs_path = "~/".to_string();
         }
         cx.spawn(async move |this, cx| {