Add article pack units with Redux-cached company unit list.

Edit amount/unit on the price tile (pc×1 = no pack unit), manage units in a dialog, and keep the default pc unit non-deletable.

src/components/panels/EditablePanelTile.jsx

@@ -203,6 +203,7 @@ class EditablePanelTileBase extends Component {
       tileKey,
       renderDisplay,
       renderEdit,
+      renderOverlay,
       contentAlignItems = 'center',
     } = this.props;
     const { editing, draft, error } = this.state;
@@ -224,6 +225,13 @@ class EditablePanelTileBase extends Component {
         })}
       >
         {this.renderActions()}
+        {typeof renderOverlay === 'function'
+          ? renderOverlay({
+              editing,
+              draft,
+              onChange: this.handleDraftChange,
+            })
+          : null}
         {this.renderTitle()}
         <Box
           sx={{