feat: migrate out of the flat store layout

src/cli/link.rs

@@ -19,6 +19,15 @@ pub enum Link {
 
     /// List untracked paths a sandbox would still see
     Check(Check),
+
+    /// Move this checkout's paths from the old store layout into its own directory
+    Migrate(Migrate),
+}
+
+#[derive(Args, Debug)]
+pub struct Migrate {
+    #[command(flatten)]
+    pub store: Store,
 }
 
 #[derive(Args, Debug)]