fix: reopen hidden desktop decision history

Reveal the existing history panel on repeated clicks without losing responsive history behavior. Cover hiding and reopening the already-open tab.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/coordinator/CoordinatorNeedsYou.test.tsx

@@ -209,5 +209,11 @@ describe("Coordinator Needs You", () => {
     await click("Decision history");
     expect(fixture.openPanel).toHaveBeenCalled();
     expect(fixture.setPanelVisible).toHaveBeenCalledWith(true);
+    // The shared desktop hide control changes visibility without closing
+    // this tab. Clicking history again must reveal the already-open tab.
+    fixture.setPanelVisible(false);
+    fixture.setPanelVisible.mockClear();
+    await click("Decision history");
+    expect(fixture.setPanelVisible).toHaveBeenCalledWith(true);
   });
 });

ui/src/components/coordinator/CoordinatorNeedsYou.tsx

@@ -149,7 +149,7 @@ export function CoordinatorNeedsYou() {
   ]).entries()], [pendingItems, recentItems]);
   const filtersActive = Boolean(query.trim() || agentFilter || projectFilter);
   const closeHistory = useCallback(() => { setHistoryOpen(false); closePanel(); }, [closePanel]);
-  const showHistory = () => setHistoryOpen(true);
+  const showHistory = () => { setHistoryOpen(true); if (!isMobile) setPanelVisible(true); };
   useEffect(() => { setBreadcrumbs([{ label: "Needs You" }]); }, [setBreadcrumbs]);
   useEffect(() => {
     setSettling([]); setHistoryOpen(false); setNow(Date.now()); closePanel();