feat(select): Previous / Last keywords at Select objects prompts

Standard selection keywords, available typed or as prompt buttons in
every gathering command (#426): P / PREVIOUS re-selects the set the
last finishing command worked on (now captured before the working set
is dropped), and L / LAST selects the most recently created object of
the current space (highest handle among its selectable wires). Handled
centrally in the step router, so the command line, the option buttons
and the automation feeder share one implementation; deleted objects
and locked layers are filtered out.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/app/update/command.rs

@@ -254,6 +254,11 @@ pub(super) fn on_tab_close(&mut self, idx: usize) -> Task<Message> {
                     // text falls through to the Enter / coordinate handling
                     // below, so a bare Enter still terminates and typed points
                     // still work when dynamic input is off. See #97.
+                    // Selection keywords (P / L) at a Select objects prompt
+                    // consume the token before any other interpretation (#426).
+                    if let Some(task) = self.try_selection_keyword(&text) {
+                        return task;
+                    }
                     if self.tabs[i]
                         .active_cmd
                         .as_ref()