feat: Lead Master — column show/hide toggle, resizable table, remove dead filter/sort buttons

- ColumnToggle component with checkbox dropdown for column visibility
- useColumnVisibility hook for state management
- Campaign/Ad/FirstContact/Spam/Dups hidden by default (mostly empty)
- ResizableTableContainer wrapping Table for column resize support
- Column defaultWidth/minWidth props
- Removed non-functional Filter and Sort buttons

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/application/table/table.tsx

@@ -17,7 +17,9 @@ import {
     Cell as AriaCell,
     Collection as AriaCollection,
     Column as AriaColumn,
+    ColumnResizer as AriaColumnResizer,
     Group as AriaGroup,
+    ResizableTableContainer as AriaResizableTableContainer,
     Row as AriaRow,
     Table as AriaTable,
     TableBody as AriaTableBody,
@@ -115,9 +117,9 @@ const TableRoot = ({ className, size = "md", ...props }: TableRootProps) => {
 
     return (
         <TableContext.Provider value={{ size: context?.size ?? size }}>
-            <div className="flex-1 overflow-auto min-h-0">
+            <AriaResizableTableContainer className="flex-1 overflow-auto min-h-0">
                 <AriaTable className={(state) => cx("w-full", typeof className === "function" ? className(state) : className)} {...props} />
-            </div>
+            </AriaResizableTableContainer>
         </TableContext.Provider>
     );
 };
@@ -168,9 +170,10 @@ TableHeader.displayName = "TableHeader";
 interface TableHeadProps extends AriaColumnProps, Omit<ThHTMLAttributes<HTMLTableCellElement>, "children" | "className" | "style" | "id"> {
     label?: string;
     tooltip?: string;
+    allowsResizing?: boolean;
 }
 
-const TableHead = ({ className, tooltip, label, children, ...props }: TableHeadProps) => {
+const TableHead = ({ className, tooltip, label, children, allowsResizing, ...props }: TableHeadProps) => {
     const { selectionBehavior } = useTableOptions();
 
     return (
@@ -186,8 +189,8 @@ const TableHead = ({ className, tooltip, label, children, ...props }: TableHeadP
             }
         >
             {(state) => (
-                <AriaGroup className="flex items-center gap-1">
-                    <div className="flex items-center gap-1">
+                <AriaGroup className="flex items-center gap-1" role="presentation">
+                    <div className="flex items-center gap-1 flex-1 min-w-0">
                         {label && <span className="text-xs font-semibold whitespace-nowrap text-quaternary">{label}</span>}
                         {typeof children === "function" ? children(state) : children}
                     </div>
@@ -206,6 +209,10 @@ const TableHead = ({ className, tooltip, label, children, ...props }: TableHeadP
                         ) : (
                             <FontAwesomeIcon icon={faSort} className="text-fg-quaternary" />
                         ))}
+
+                    {allowsResizing && (
+                        <AriaColumnResizer className="absolute top-0 right-0 bottom-0 w-1 cursor-col-resize bg-transparent hover:bg-brand data-[resizing]:bg-brand" />
+                    )}
                 </AriaGroup>
             )}
         </AriaColumn>