Add widget-control logic action and multi-column CSV / multi-field dialogs

Extend the panel logic editor with two capabilities:

- action.widget: drive a panel widget by id from a flow — enable/disable,
  show/hide, and (for plot widgets) clear, pause, or resume the live plot.
  Wired via a per-widget command store consumed by a Canvas WidgetView wrapper
  (disable overlay / hide) and PlotWidget (pause/clear), reset on panel unmount.
- action.export now emits multiple named arrays as CSV columns with per-column
  labels and an alignment mode (common/any/interpolate); dialogs support asking
  for and displaying multiple values per dialog.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/EditMode.tsx

@@ -682,6 +682,7 @@ export default function EditMode({ initial, onDone }: Props) {
             <LogicEditor
               graph={iface.logic ?? { nodes: [], wires: [] }}
               onChange={handleLogicChange}
+              widgets={iface.widgets}
               statevars={iface.statevars}
               onStateVarsChange={handleStateVarsChange}
             />