Fix swipe-to-dismiss on sets page mobile bottom sheet

src/pages/SetsPage.jsx

@@ -110,6 +110,42 @@ function SetsPage() {
   const [searchTerm, setSearchTerm] = useState('');
   const [expandedCardId, setExpandedCardId] = useState(null);
   const isMobile = useMediaQuery('(max-width: 768px)');
+  const sheetRef = React.useRef(null);
+  const handleRef = React.useRef(null);
+  const dragStartY = React.useRef(null);
+
+  const closeSheet = React.useCallback(() => { setSelectedSet(null); setSetCards([]); }, []);
+
+  React.useEffect(() => {
+    const handle = handleRef.current;
+    if (!handle) return;
+
+    const onStart = e => { dragStartY.current = e.touches[0].clientY; };
+    const onMove = e => {
+      e.preventDefault();
+      const dy = e.touches[0].clientY - dragStartY.current;
+      if (dy > 0 && sheetRef.current) sheetRef.current.style.transform = `translateY(${dy}px)`;
+    };
+    const onEnd = e => {
+      const dy = e.changedTouches[0].clientY - dragStartY.current;
+      if (dy > 80) {
+        closeSheet();
+      } else if (sheetRef.current) {
+        sheetRef.current.style.transition = 'transform 0.2s ease';
+        sheetRef.current.style.transform = '';
+        setTimeout(() => { if (sheetRef.current) sheetRef.current.style.transition = ''; }, 200);
+      }
+    };
+
+    handle.addEventListener('touchstart', onStart, { passive: true });
+    handle.addEventListener('touchmove', onMove, { passive: false });
+    handle.addEventListener('touchend', onEnd, { passive: true });
+    return () => {
+      handle.removeEventListener('touchstart', onStart);
+      handle.removeEventListener('touchmove', onMove);
+      handle.removeEventListener('touchend', onEnd);
+    };
+  }, [selectedSet, closeSheet]);
 
   useEffect(() => {
     fetchSets().then(setSets).catch(console.error).finally(() => setLoading(false));
@@ -204,9 +240,9 @@ function SetsPage() {
       {/* Mobile: bottom sheet */}
       {isMobile && selectedSet && (
         <>
-          <div className="sheet-backdrop" onClick={() => { setSelectedSet(null); setSetCards([]); }} />
-          <div className="bottom-sheet">
-            <div className="sheet-handle-area"><div className="sheet-handle" /></div>
+          <div className="sheet-backdrop" onClick={closeSheet} />
+          <div ref={sheetRef} className="bottom-sheet">
+            <div ref={handleRef} className="sheet-handle-area"><div className="sheet-handle" /></div>
             {setDetail}
           </div>
         </>