fix(global-search): surface unreachable nodes and harden the command palette (#1253)

* fix(global-search): surface unreachable nodes and harden the command palette

The command palette discarded the cross-node search hook's failedNodes, so a search run while a fleet node was down silently returned partial results with no sign a host was skipped. It now renders an "N nodes unreachable" line and still shows the stacks it could gather.

The shared cross-node search hook fetched every node's stack list and statuses on every keystroke. It now fans out once per search session and filters the cached inventory client-side as the query is refined, cutting per-keystroke fleet traffic. A 200 response with an unparseable status body degrades stacks to unknown instead of failing the whole node.

The palette now owns result matching (cmdk's built-in fuzzy filter is disabled), so Pages, Nodes, and Stacks match by case-insensitive substring in a deterministic order and the 50-row cap applies to the real match set rather than a re-sorted slice.

Adds unit coverage for the hook and palette, plus a Playwright journey spec.

* fix(global-search): clear stale cross-node results when the active node changes

When excludeNodeId changed mid-search (the sidebar switches it on active-node change), the hook started a fresh fanout but left the previous session's inventory and failedNodes visible until the refetch resolved, so the newly active node could briefly appear under the other-nodes results or a stale unreachable warning could persist. The new session now drops prior results synchronously before refetching.

frontend/src/components/__tests__/GlobalCommandPalette.test.tsx

@@ -0,0 +1,195 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { Home, Radar } from 'lucide-react';
+import type { Node } from '@/context/NodeContext';
+import type { StackHit, FailedNode } from '@/hooks/useCrossNodeStackSearch';
+import type { TopBarNavItem } from '../TopBar';
+
+let hookReturn: { hits: StackHit[]; failedNodes: FailedNode[]; loading: boolean };
+vi.mock('@/hooks/useCrossNodeStackSearch', () => ({
+  useCrossNodeStackSearch: () => hookReturn,
+}));
+
+const setActiveNodeMock = vi.fn();
+let nodesValue: { nodes: Node[]; activeNode: Node | null; setActiveNode: (n: Node) => void };
+vi.mock('@/context/NodeContext', () => ({
+  useNodes: () => nodesValue,
+}));
+
+import {
+  GlobalCommandPaletteProvider,
+  GlobalCommandPaletteTrigger,
+  GlobalCommandPalette,
+} from '../GlobalCommandPalette';
+
+// cmdk scrolls the active item into view; jsdom has no scrollIntoView.
+Element.prototype.scrollIntoView = () => {};
+
+function node(id: number, name: string, status: Node['status'] = 'online'): Node {
+  return {
+    id,
+    name,
+    type: id === 1 ? 'local' : 'remote',
+    compose_dir: '/compose',
+    is_default: id === 1,
+    status,
+    created_at: 0,
+  };
+}
+
+const navItems: TopBarNavItem[] = [
+  { value: 'dashboard', label: 'Home', icon: Home },
+  { value: 'fleet', label: 'Fleet', icon: Radar },
+];
+
+const onNavigate = vi.fn();
+const onSelectStack = vi.fn();
+
+function renderPalette() {
+  return render(
+    <GlobalCommandPaletteProvider>
+      <GlobalCommandPaletteTrigger />
+      <GlobalCommandPalette navItems={navItems} onNavigate={onNavigate} onSelectStack={onSelectStack} />
+    </GlobalCommandPaletteProvider>,
+  );
+}
+
+function open() {
+  fireEvent.click(screen.getByLabelText('Open search (Ctrl+K)'));
+}
+
+function type(value: string) {
+  fireEvent.change(screen.getByPlaceholderText('Search the app...'), { target: { value } });
+}
+
+beforeEach(() => {
+  hookReturn = { hits: [], failedNodes: [], loading: false };
+  nodesValue = {
+    nodes: [node(1, 'local'), node(2, 'opsix')],
+    activeNode: node(1, 'local'),
+    setActiveNode: setActiveNodeMock,
+  };
+  onNavigate.mockReset();
+  onSelectStack.mockReset();
+  setActiveNodeMock.mockReset();
+});
+
+describe('GlobalCommandPalette', () => {
+  it('opens on trigger click and lists Pages and Nodes', () => {
+    renderPalette();
+    open();
+    expect(screen.getByText('Home')).toBeInTheDocument();
+    expect(screen.getByText('Fleet')).toBeInTheDocument();
+    expect(screen.getByText('local')).toBeInTheDocument();
+    expect(screen.getByText('opsix')).toBeInTheDocument();
+  });
+
+  it('filters pages and nodes by substring (palette owns matching)', () => {
+    renderPalette();
+    open();
+    type('fleet');
+    expect(screen.getByText('Fleet')).toBeInTheDocument();
+    expect(screen.queryByText('Home')).not.toBeInTheDocument();
+    // 'fleet' matches no node name.
+    expect(screen.queryByText('local')).not.toBeInTheDocument();
+    expect(screen.queryByText('opsix')).not.toBeInTheDocument();
+  });
+
+  it('surfaces a single unreachable node, even with zero hits', () => {
+    hookReturn = {
+      hits: [],
+      failedNodes: [{ nodeId: 2, nodeName: 'opsix', reason: 'list returned HTTP 502' }],
+      loading: false,
+    };
+    renderPalette();
+    open();
+    type('zzz');
+    expect(screen.getByText(/1 node unreachable/i)).toBeInTheDocument();
+  });
+
+  it('pluralises the unreachable-node count', () => {
+    hookReturn = {
+      hits: [],
+      failedNodes: [
+        { nodeId: 2, nodeName: 'opsix', reason: 'down' },
+        { nodeId: 3, nodeName: 'edge', reason: 'down' },
+      ],
+      loading: false,
+    };
+    renderPalette();
+    open();
+    type('zzz');
+    expect(screen.getByText(/2 nodes unreachable/i)).toBeInTheDocument();
+  });
+
+  it('shows stack hits and the unreachable line together (partial results)', () => {
+    hookReturn = {
+      hits: [{ nodeId: 2, nodeName: 'opsix', file: 'db.yml', status: 'running' }],
+      failedNodes: [{ nodeId: 3, nodeName: 'edge', reason: 'down' }],
+      loading: false,
+    };
+    renderPalette();
+    open();
+    type('db');
+    expect(screen.getByText('db.yml')).toBeInTheDocument();
+    expect(screen.getByText(/1 node unreachable/i)).toBeInTheDocument();
+    // "No results." is suppressed: there are hits, and a node failed.
+    expect(screen.queryByText('No results.')).not.toBeInTheDocument();
+  });
+
+  it('renders stack hits and caps the list with an overflow line', () => {
+    const hits: StackHit[] = Array.from({ length: 55 }, (_, i) => ({
+      nodeId: 2,
+      nodeName: 'opsix',
+      file: `s${i}.yml`,
+      status: 'running',
+    }));
+    hookReturn = { hits, failedNodes: [], loading: false };
+    renderPalette();
+    open();
+    type('s');
+    expect(screen.getByText('Showing first 50 of 55')).toBeInTheDocument();
+    expect(screen.getByText('s0.yml')).toBeInTheDocument();
+    expect(screen.queryByText('s54.yml')).not.toBeInTheDocument();
+  });
+
+  it('navigates and closes when a page is selected', async () => {
+    renderPalette();
+    open();
+    fireEvent.click(screen.getByText('Fleet'));
+    expect(onNavigate).toHaveBeenCalledWith('fleet');
+    // The animated dialog stays mounted briefly in jsdom; assert it left the
+    // open state rather than depending on unmount timing.
+    await waitFor(() => {
+      const dialog = screen.queryByRole('dialog');
+      expect(dialog?.getAttribute('data-state') ?? 'unmounted').not.toBe('open');
+    });
+  });
+
+  it('disables an offline node row', () => {
+    nodesValue = {
+      nodes: [node(1, 'local'), node(2, 'opsix', 'offline')],
+      activeNode: node(1, 'local'),
+      setActiveNode: setActiveNodeMock,
+    };
+    renderPalette();
+    open();
+    const row = screen.getByText('opsix').closest('[cmdk-item]');
+    expect(row).toHaveAttribute('data-disabled', 'true');
+  });
+
+  it('shows "No results." when nothing matches and nothing is loading', () => {
+    renderPalette();
+    open();
+    type('zzzz');
+    expect(screen.getByText('No results.')).toBeInTheDocument();
+  });
+
+  it('shows "Searching..." while stacks load and nothing else matches', () => {
+    hookReturn = { hits: [], failedNodes: [], loading: true };
+    renderPalette();
+    open();
+    type('zzzz');
+    expect(screen.getByText('Searching...')).toBeInTheDocument();
+  });
+});