fix(ui): bottom sheets on phones are square at the bottom like the other sheets

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/components/FormSheet.tsx

@@ -16,7 +16,8 @@ interface FormSheetProps {
 }
 
 // Small create/rename dialogs. Phone: bottom sheet directly above the keyboard, full width, large
-// fields. Desktop: centred dialog (or next to the click). Escape and the backdrop close it.
+// fields, square at the bottom with only a top border (like the other sheets: it docks to the keyboard
+// even with a rounded theme, whose panel-surface would round all corners). Desktop: centred dialog (or next to the click). Escape and the backdrop close it.
 export const FormSheet: React.FC<FormSheetProps> = ({
   title,
   icon,
@@ -56,7 +57,7 @@ export const FormSheet: React.FC<FormSheetProps> = ({
             '--vv-max': visibleHeight ? `${visibleHeight - 16}px` : '85vh',
           } as React.CSSProperties
         }
-        className={`fixed inset-x-0 bottom-[var(--kb-inset)] max-h-[var(--vv-max)] panel-surface rounded-t-2xl border-t border-border shadow-panel p-4 space-y-3 overflow-y-auto
+        className={`fixed inset-x-0 bottom-[var(--kb-inset)] max-h-[var(--vv-max)] panel-surface rounded-t-2xl rounded-b-none border-x-0 border-b-0 border-t border-border shadow-panel p-4 space-y-3 overflow-y-auto
           sm:inset-x-auto sm:bottom-auto sm:max-h-[85vh] sm:w-full sm:rounded-card sm:border ${
             anchor
               ? 'sm:max-w-[16.5rem] sm:left-[var(--sheet-x)] sm:top-[var(--sheet-y)]'