Command line: hovered history lines stay until the pointer leaves

Lines still showing when the pointer reaches the overlay history no
longer fade under it; leaving restarts their COMMANDLINEFADETIME.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/update/mod.rs

@@ -2857,6 +2857,11 @@ impl OpenCADStudio {
                 self.focus_cmd_input()
             }
 
+            Message::CommandHistoryHover(hovered) => {
+                self.command_line.set_history_hover(hovered);
+                Task::none()
+            }
+
             Message::CommandHistoryToggle => {
                 self.command_line.toggle_history();
                 if !self.command_line.history_open {