fix(ui): collapse the sidebar atomically, ignoring the lingering hover (PAP-10676)

Clicking the collapse button switched to rail mode but the pointer was still over
the panel, so the peek logic immediately re-expanded it — the collapse only
"took" once the mouse moved away.

Fix in Layout's peek wiring:
- Track pointer-over-panel even while expanded (mouse enter/leave handlers are now
  always wired, but only open a peek when collapsed), so at the moment of collapse
  we know the pointer is still over the sidebar.
- On the expanded→collapsed transition, cancel any pending/active peek
  (clearPeekTimer + setPeeking(false)) and, when the pointer is still inside, set a
  suppress flag so the lingering hover can't re-open the peek. The flag is re-armed
  on the next genuine pointer-leave, so normal hover-to-peek still works afterwards.
- Focus-driven peek respects the same suppress flag.

Tests: added a Layout test that collapses while hovering and asserts the peek is
cancelled and does not re-open, plus a positive-control test proving a normal
collapsed-rail hover still opens the peek (so the suppression test is meaningful).
70 sidebar+layout tests pass; tsc clean.

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

ui/src/components/Layout.test.tsx

@@ -334,6 +334,33 @@ describe("Layout", () => {
     await act(async () => { root.unmount(); });
   });
 
+  it("opens the peek when hovering a collapsed rail (positive control for the hover sim)", async () => {
+    mockSidebarState.collapsed = true;
+    const root = createRoot(container);
+    const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+    await act(async () => {
+      root.render(
+        <QueryClientProvider client={queryClient}>
+          <Layout />
+        </QueryClientProvider>,
+      );
+    });
+    await flushReact();
+
+    const panel = [...container.querySelectorAll<HTMLElement>("div")].find(
+      (el) => el.className.includes("inset-y-0") && el.className.includes("overflow-hidden"),
+    );
+    expect(panel).toBeTruthy();
+    await act(async () => {
+      panel!.dispatchEvent(new MouseEvent("mouseover", { bubbles: true, relatedTarget: document.body }));
+    });
+    await act(async () => { await new Promise((r) => setTimeout(r, 80)); });
+    // A normal collapsed-rail hover (not just-collapsed) opens the peek.
+    expect(mockSetPeeking).toHaveBeenCalledWith(true);
+
+    await act(async () => { root.unmount(); });
+  });
+
   it("keeps the app sidebar and shows the settings sidebar in the secondary pane on settings routes", async () => {
     currentPathname = "/PAP/company/settings/access";
     mockPluginSlots.slots = [