Make SolveApp::start honour a command's enabled flag, and disable solid.move inside a sketch (#740)

`SolveApp::start` now honours a command's enabled flag, so shortcuts, the command palette and the control channel can't start a disabled command, and Move is disabled while a sketch is open.

crates/ui-egui/src/lib.rs

@@ -530,6 +530,16 @@ impl SolveApp {
         if self.file_load.busy() {
             return;
         }
+        // A disabled command starts nothing, however it was reached. The toolbar greys its
+        // button, but a shortcut, the command palette and the control channel all land here.
+        // Its reason goes to the status line, so the refusal is never silent.
+        if let Some(info) = solidcraft_engine::find_command(id).map(|c| c.info(&self.session))
+            && let Some(why) = info.disabled_reason
+        {
+            let label = self.tr_label(info.label).to_string();
+            self.set_status(format!("{label}: {why}"), true);
+            return;
+        }
         // Another command ends Edit Text (its dialog is not a feature edit to keep).
         sketch_text_move::cancel_drag(self);
         if sketch_text::editing(self) || self.dialog.as_ref().is_some_and(|d| matches!(d.kind, dialogs::Kind::TextMove(_))) {