Worktree paths in git panel, take 2 (#26047)

Modified version of #25950. We still use worktree paths, but repo paths
with a status that lie outside the worktree are not excluded; instead,
we relativize them by adding `..`. This makes the list in the git panel
match what you'd get from running `git status` (with the repo's worktree
root as the working directory).

- [x] Implement + test new unrelativization logic
- [x] ~~When collecting repositories, dedup by .git abs path, so
worktrees can share a repo at the project level~~ dedup repos at the
repository selector layer, with repos coming from larger worktrees being
preferred
- [x] Open single-file worktree with diff when activating a path not in
the worktree

Release Notes:

- N/A

crates/workspace/src/pane.rs

@@ -7,8 +7,8 @@ use crate::{
     notifications::NotifyResultExt,
     toolbar::Toolbar,
     workspace_settings::{AutosaveSetting, TabBarSettings, WorkspaceSettings},
-    CloseWindow, NewFile, NewTerminal, OpenInTerminal, OpenTerminal, OpenVisible, SplitDirection,
-    ToggleFileFinder, ToggleProjectSymbols, ToggleZoom, Workspace,
+    CloseWindow, NewFile, NewTerminal, OpenInTerminal, OpenOptions, OpenTerminal, OpenVisible,
+    SplitDirection, ToggleFileFinder, ToggleProjectSymbols, ToggleZoom, Workspace,
 };
 use anyhow::Result;
 use collections::{BTreeSet, HashMap, HashSet, VecDeque};
@@ -3086,7 +3086,10 @@ impl Pane {
                         }
                         workspace.open_paths(
                             paths,
-                            OpenVisible::OnlyDirectories,
+                            OpenOptions {
+                                visible: Some(OpenVisible::OnlyDirectories),
+                                ..Default::default()
+                            },
                             Some(to_pane.downgrade()),
                             window,
                             cx,