Key tips: translate the hints, drop a held Alt on focus loss

Alt+Tab away left the lone-Alt flag set, so the release on return
opened the key tips.

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

src/app/update/mod.rs

@@ -629,7 +629,11 @@ impl OpenCADStudio {
                 if Some(id) == self.main_window {
                     self.spacemouse_focused = focused;
                 }
-                // Key tips close when the window loses the focus.
+                // Key tips close when the window loses the focus, and an Alt
+                // held while it left (Alt+Tab) no longer counts as a lone tap.
+                if !focused {
+                    crate::ui::ribbon::keytip_pointer_pressed();
+                }
                 if !focused && self.ribbon.keytips_active() {
                     return self.hide_keytips();
                 }