fix: ensure filter popovers appear above pinned columns

- Add zIndex prop to ColumnFilterPopover and TextFilterPopover
- Pass higher zIndex to popovers when column is pinned (zIndex + 100)
- Filter popovers now display correctly over sticky columns

src/components/ColumnFilterPopover.tsx

@@ -19,6 +19,7 @@ interface ColumnFilterPopoverProps {
   onClose: () => void;
   title?: string;
   className?: string;
+  zIndex?: number;
 }
 
 export function ColumnFilterPopover({
@@ -29,7 +30,8 @@ export function ColumnFilterPopover({
   onClear,
   onClose,
   title,
-  className
+  className,
+  zIndex = 50
 }: ColumnFilterPopoverProps) {
   const [search, setSearch] = useState('');
   const [activeTab, setActiveTab] = useState<'values' | 'condition'>('values');
@@ -157,9 +159,10 @@ export function ColumnFilterPopover({
   return (
     <div
       className={cn(
-        "absolute top-full left-0 mt-1 w-72 bg-slate-800 border border-slate-700 rounded-lg shadow-2xl z-50 p-3 flex flex-col gap-3 animate-in fade-in zoom-in-95 duration-100",
+        "absolute top-full left-0 mt-1 w-72 bg-slate-800 border border-slate-700 rounded-lg shadow-2xl p-3 flex flex-col gap-3 animate-in fade-in zoom-in-95 duration-100",
         className
       )}
+      style={{ zIndex }}
       onClick={(e) => e.stopPropagation()}
     >
       <button