Bind the two develop gestures that were described and not bound

FR-DEV-16's book said resetting a control and hiding a mask layer were
reachable by pointer and by finger, and stopped there. The reason was
honest: the generated rows have no focus, so "reset the focused control"
named a thing the panel could not point at. But a photographer at the
keyboard means something narrower than focus. They mean the slider they
just dragged too far, and that is a thing the panel can remember.

So the Adjustments global keeps the last control moved — two indices,
written where the panel forwards the change and cleared when the next
photograph opens, so a reset cannot reach back into the previous edit
through an index that happens to be shared. R puts it back, through the
same callback the track's double-click takes, and is silent until
something has moved.

The mask layer needs no such notion, because the panel already has a
selection: the rows the edge controls point at. H hides or shows those,
through the path the ring at the head of the row takes, so it is an edit
and a history step exactly as the ring is. A mixed selection goes to
shown, since the layer nobody can see is the one being asked about.

Both tags now carry the key, and the book says so.

ui/dr-ui/src/masks_ui.rs

@@ -666,6 +666,34 @@ pub(crate) fn wire(
         });
     }
     {
+    {
+        // TRACES: FR-DEV-16
+        // The keyboard's copy of the ring. A mixed selection goes to shown:
+        // a layer nobody can see is the one being asked about, and turning
+        // the rest off to match it would hide work in the name of hiding it.
+        let weak = window.as_weak();
+        let session = session.clone();
+        let redraw = redraw.clone();
+        window.global::<Masking>().on_selected_toggled(move || {
+            let Some(w) = weak.upgrade() else { return };
+            {
+                let mut slot = session.borrow_mut();
+                let Some(s) = slot.as_mut() else { return };
+                let ids: Vec<String> = s.active_masks().to_vec();
+                if ids.is_empty() {
+                    return;
+                }
+                let all_shown = ids
+                    .iter()
+                    .all(|id| s.masks().get(id).is_some_and(|l| l.enabled));
+                for id in &ids {
+                    s.set_mask_enabled(id, !all_shown);
+                }
+            }
+            sync(&w, &session);
+            redraw(&w);
+        });
+    }
         let weak = window.as_weak();
         let session = session.clone();
         let redraw = redraw.clone();