task: Add ZED_DIRNAME and ZED_RELATIVE_FILE task variables (#12245)

Release Notes:

- Added ZED_RELATIVE_FILE (path to current file relative to worktree
root) and ZED_DIRNAME (path to the directory containing current file)
task variables.

crates/project/Cargo.toml

@@ -44,6 +44,7 @@ log.workspace = true
 lsp.workspace = true
 node_runtime.workspace = true
 parking_lot.workspace = true
+pathdiff.workspace = true
 postage.workspace = true
 prettier.workspace = true
 worktree.workspace = true