Allow running zeta evals against sweep (#43039)

This PR restructures the subcommands in `zeta-cli`, so that the
prediction engine (currently `zeta1` vs `zeta2`) is no longer the
highest order subcommand. Instead, there is just one layer of
subcommands: `eval`, `predict`, `context`, etc. Within these commands,
there are flags for using `zeta1`, `zeta2`, and now `sweep`.

Release Notes:

- N/A

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Agus <agus@zed.dev>

crates/workspace/src/workspace.rs

@@ -1845,7 +1845,7 @@ impl Workspace {
     pub fn recent_navigation_history_iter(
         &self,
         cx: &App,
-    ) -> impl Iterator<Item = (ProjectPath, Option<PathBuf>)> {
+    ) -> impl Iterator<Item = (ProjectPath, Option<PathBuf>)> + use<> {
         let mut abs_paths_opened: HashMap<PathBuf, HashSet<ProjectPath>> = HashMap::default();
         let mut history: HashMap<ProjectPath, (Option<PathBuf>, usize)> = HashMap::default();