Show only the photographs taken in the period you are looking at

The library could be narrowed by rating, flag and availability, but not
by when a photograph was taken — so finding a fortnight meant scrolling
to it and holding position.

The range rides on `RatingFilter` for the reason `local_only` already
does: every query path threads that one struct, so the count in the
header cannot claim a total the grid does not draw. Undated images are
excluded whenever either end is set — they cannot be inside or outside a
span, and drawing them made the range look as though it had not applied.

Taken from the timeline rather than typed into two date fields. Finding
the period is what the histogram is for, and having found it the user
should not have to read the dates off the axis and key them back in.
The histogram keeps drawing the full extent while the range is on, or
there would be nowhere to widen back out from.

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

ui/dr-ui/src/library_ui.rs

@@ -3645,6 +3645,50 @@ pub fn wire<F>(
         });
     }
 
+    // Narrow the grid to the period the histogram is showing.
+    //
+    // The range is taken from the timeline rather than typed into two date
+    // fields: finding the fortnight is what the histogram is *for*, and having
+    // found it the user should not have to read the dates off the axis and key
+    // them back in. Zoom, then say "only that".
+    //
+    // Toggling off clears both ends rather than remembering them — a range you
+    // cannot see the extent of is a filter that looks like an empty library.
+    {
+        let weak = window.as_weak();
+        let ctl = ctl.clone();
+        window.on_library_toggle_date_range(move || {
+            let Some(w) = weak.upgrade() else { return };
+            let on = !ctl.filter.borrow().has_date_range();
+            if on {
+                // The span the axis is currently drawn over, which is what the
+                // user is looking at when they ask for "this range".
+                let borrow = ctl.catalog.borrow();
+                let Some(catalog) = borrow.as_ref() else {
+                    return;
+                };
+                let Some(span) = catalog_span(catalog, &ctl) else {
+                    return;
+                };
+                let (from, to) = zoomed_span(
+                    span,
+                    *ctl.timeline_zoom.borrow(),
+                    *ctl.timeline_centre.borrow(),
+                );
+                drop(borrow);
+                let mut f = ctl.filter.borrow_mut();
+                f.captured_from = Some(from);
+                f.captured_to = Some(to);
+            } else {
+                let mut f = ctl.filter.borrow_mut();
+                f.captured_from = None;
+                f.captured_to = None;
+            }
+            w.set_library_range_active(on);
+            refilter(&w, &ctl);
+        });
+    }
+
     // TRACES: FR-CAT-9
     // "On this device" — the images openable without a server. Composes with
     // the rating terms rather than replacing them: "five-star frames I can