fix: react-doctor modal/dialog/dropzone a11y — 18 files to role+tabIndex+onKeyDown or dialog

src/context/CartContext.tsx

@@ -256,10 +256,14 @@ export function CartProvider({ children }: { children: ReactNode }) {
   }, []);
 
   const decreaseQuantity = useCallback((id: string) => {
-    setCart((prev) =>
-      prev.map((item) => (item.id === id ? { ...item, quantity: item.quantity - 1 } : item))
-      .filter((item) => item.quantity > 0)
-    );
+    setCart((prev) => {
+      const next = [];
+      for (const item of prev) {
+        const updated = item.id === id ? { ...item, quantity: item.quantity - 1 } : item;
+        if (updated.quantity > 0) next.push(updated);
+      }
+      return next;
+    });
   }, []);
 
   const removeFromCart = useCallback((id: string) => {