feat(widgets): unify data table behavior

apps/docs/docs/widgets/beszel-system-table/index.mdx

@@ -23,7 +23,7 @@ Select a system row to open the complete statistics view, including system, file
 
 ### Interactions
 
-- **Reorder columns** by dragging their headers
+- **Reorder columns** by hovering a header to reveal its grab handle, then dragging it
 - **Resize columns** by dragging a header's right edge
 - **Sort systems** by selecting a sortable column header
 - **Open system statistics** by selecting a row

apps/docs/docs/widgets/docker-containers/index.mdx

@@ -40,7 +40,7 @@ import dockerTable from './img/table.png';
 
 ### Interactions
 
-Drag column headers to reorder them and drag a header's edge to resize it. The layout is saved automatically for each widget instance and restored after a reload. These controls are disabled while the board is in edit mode.
+Hover a column header to reveal its grab handle, then drag it to reorder the table or drag the header's edge to resize it. The layout is saved automatically for each widget instance and restored after a reload. These controls are disabled while the board is in edit mode.
 
 Each container row has an action menu, accessible via the three-dot icon or by right-clicking the row, with the following options:
 

apps/docs/docs/widgets/downloads/index.mdx

@@ -44,7 +44,7 @@ import contextMenuImg from './img/context-menu.png';
 
 - **Responsive table** — columns automatically adapt to widget width, hiding less important columns at smaller sizes
 - **Sortable columns** — click any column header to sort ascending/descending
-- **Column customization** — choose which columns to display via the widget options panel
+- **Column customization** — choose which columns to display, then hover a header to reveal its grab handle for reordering or drag its edge to resize it; layouts save automatically per widget
 - **Right-click context menu** — pause, resume, delete downloads, or copy download names directly from the context menu
 - **Row expansion** — click any row to see full details inline without opening a separate modal
 - **Hover tooltips** — hover a download name to see size, speeds, ETA, ratio, and category