Find working expand depth control: view.set_depth + plugin.draw

After testing plugin_config.expand_depth (no effect) and view.set_depth
+ flush() (no effect), confirmed that view.set_depth(d) followed by
plugin.draw(view) correctly collapses/expands all rows to depth d.

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

ui/src/pages/Pivot.jsx

@@ -290,13 +290,21 @@ export default function Pivot({ source }) {
         {/* expand_depth test buttons */}
         <div className="ml-auto flex items-center gap-1">
           <span className="text-xs text-gray-300">expand test:</span>
+          <button onClick={async () => {
+            const v = viewerRef.current; if (!v) return
+            const view = await v.getView()
+            const viewMethods = Object.getOwnPropertyNames(Object.getPrototypeOf(view))
+            console.log('view methods:', viewMethods)
+          }} className="text-xs border border-gray-200 rounded px-1.5 py-0.5 text-gray-500 hover:border-gray-400">
+            log
+          </button>
           {[0, 1, 2, 3].map(d => (
             <button key={d} onClick={async () => {
               const v = viewerRef.current; if (!v) return
-              const cfg = await v.save()
+              const view = await v.getView()
-              const next = { ...cfg, plugin_config: { ...cfg.plugin_config, expand_depth: d } }
+              await view.set_depth(d)
-              console.log('trying plugin_config expand_depth:', d, next)
+              const p = await v.getPlugin()
-              await v.restore(next)
+              await p.draw(view)
             }} className="text-xs border border-gray-200 rounded px-1.5 py-0.5 text-gray-500 hover:border-gray-400">
               {d}
             </button>