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/project_panel/src/project_panel.rs

@@ -59,7 +59,8 @@ use util::{maybe, paths::compare_paths, ResultExt, TakeUntilExt, TryFutureExt};
 use workspace::{
     dock::{DockPosition, Panel, PanelEvent},
     notifications::{DetachAndPromptErr, NotifyTaskExt},
-    DraggedSelection, OpenInTerminal, PreviewTabsSettings, SelectedEntry, Workspace,
+    DraggedSelection, OpenInTerminal, OpenOptions, OpenVisible, PreviewTabsSettings, SelectedEntry,
+    Workspace,
 };
 use worktree::{CreatedEntry, GitEntry, GitEntryRef};
 
@@ -1211,7 +1212,7 @@ impl ProjectPanel {
                                 project_panel
                                     .workspace
                                     .update(cx, |workspace, cx| {
-                                        workspace.open_abs_path(abs_path, true, window, cx)
+                                        workspace.open_abs_path(abs_path, OpenOptions { visible: Some(OpenVisible::All), ..Default::default() }, window, cx)
                                     })
                                     .ok()
                             }