Fix non-directory in workspace on Windows (#11833)

Fixes #11793

On Windows, trying to read a file inside what is not a directory but
another file results in a not found error, while on Unix we get a not a
directory error. We check explicitly if something included in a
workspace glob is a non-directory to fix the behavior on Windows.

crates/uv-workspace/src/workspace.rs

@@ -762,7 +762,17 @@ impl Workspace {
                 let pyproject_path = member_root.join("pyproject.toml");
                 let contents = match fs_err::tokio::read_to_string(&pyproject_path).await {
                     Ok(contents) => contents,
-                    Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                    Err(err) => {
+                        if !fs_err::metadata(&member_root)?.is_dir() {
+                            warn!(
+                                "Ignoring non-directory workspace member: `{}`",
+                                member_root.simplified_display()
+                            );
+                            continue;
+                        }
+
+                        // A directory exists, but it doesn't contain a `pyproject.toml`.
+                        if err.kind() == std::io::ErrorKind::NotFound {
                             // If the directory is hidden, skip it.
                             if member_root
                                 .file_name()
@@ -781,15 +791,9 @@ impl Workspace {
                                 member_glob.to_string(),
                             ));
                         }
-                    Err(err) if err.kind() == std::io::ErrorKind::NotADirectory => {
-                        warn!(
-                            "Ignoring non-directory workspace member: `{}`",
-                            member_root.simplified_display()
-                        );
 
-                        continue;
+                        return Err(err.into());
                     }
-                    Err(err) => return Err(err.into()),
                 };
                 let pyproject_toml = PyProjectToml::from_string(contents)
                     .map_err(|err| WorkspaceError::Toml(pyproject_path.clone(), Box::new(err)))?;

scripts/workspaces/albatross-virtual-workspace/packages/Unrelated.md

@@ -0,0 +1,2 @@
+This file is included in `packages/*`, but it is not a directory (it can't contain a package), so we
+have to ignore it.