fix(iPad): raise toolbar z-index when case settings popover is open

backdrop-filter on the toolbar creates a stacking context that traps
the popover's z-index (1000) inside the toolbar. CJK input (z-index 52)
in the root stacking context always wins. Use :has() to raise the
toolbar above CJK only while the popover is visible.

src/web/public/styles.css

@@ -2719,6 +2719,13 @@ body.solo-mode .btn-lifecycle-log {
   contain: style;
 }
 
+/* backdrop-filter creates a stacking context, trapping the popover's
+   z-index inside the toolbar. When the popover is open, raise the toolbar
+   above the CJK input (z-index 52) so the popover is interactable. */
+.toolbar:has(.case-settings-popover:not(.hidden)) {
+  z-index: 100;
+}
+
 .toolbar-left,
 .toolbar-right {
   display: flex;