test(ext): failing-test scaffold for org read UI (Plan B Tasks 1-5)

Failing tests written against Dev-A's published org SW message contract
(org_list_configs / org_switch / org_list_items / org_get_item /
org_list_collections), plus compile-clean stubs. vitest: 6 fail / 3 pass —
the 3 passes are A-independent (currentContext default + org reflect, personal
"+ new" kept); the 6 fails are exactly the org behaviors HELD until Dev-A
merges to main.

Integration (flip-on at Dev-A merge):
- org-context messageForList/messageForGet org branches (org_list_items/org_get_item)
- org-switcher org_list_configs fetch + org_switch dispatch + list reload + offline banner
- item-list org initial-load-on-render (org_list_items) + hide "+ new" in org context
- collection facet populate from org_list_collections + click-to-filter

Scaffold contents:
- shared/org-context.ts (+__tests__): currentContext complete; messageFor* personal-only (HOLD)
- shared/popup-state.ts: optional orgContext / orgOffline fields (non-breaking; A-typed
  orgConfigs/orgCollections join at integration)
- popup/components/org-switcher.ts (+__tests__): select shell only (HOLD switch + Task 5 banner)
- popup/components/__tests__/item-list.test.ts: org load + read-only (+ new hidden) assertions
- vault/vault-sidebar.ts renderCollectionFacet (+__tests__): empty container (HOLD)

Read-only this plan: write affordances stay hidden (Dev-C adds them). No org-message-type
references in src — branch stays compile-clean; build:all type-check is the integration gate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W3b8DA2mXmLWkd4zDbHXHg

extension/src/vault/__tests__/collection-facet.test.ts

@@ -0,0 +1,41 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+// renderCollectionFacet reads getState().orgCollections (shared/state). vault-sidebar
+// pulls in vault-context/vault-status/glyphs transitively; none have import-time
+// side effects, so importing it under happy-dom is safe.
+vi.mock('../../shared/state', () => ({
+  getState: vi.fn(() => ({ orgContext: 'personal', orgCollections: [] })),
+  setState: vi.fn(),
+  sendMessage: vi.fn(),
+  navigate: vi.fn(),
+  escapeHtml: (s: string) => s,
+  popOutToTab: vi.fn(),
+  isInTab: () => false,
+  openVaultTab: vi.fn(),
+}));
+
+import { renderCollectionFacet } from '../vault-sidebar';
+import { getState } from '../../shared/state';
+
+const mockGetState = getState as ReturnType<typeof vi.fn>;
+
+describe('vault collection facet (org context)', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    document.body.innerHTML = '<div id="facet"></div>';
+  });
+
+  // Task 4 — a collection nav parallel to the type-category nav, populated from
+  // org_list_collections, shown only in org context.
+  it('renders a collection facet from org_list_collections', () => {
+    mockGetState.mockReturnValue({
+      orgContext: 'org-1',
+      orgCollections: [{ slug: 'prod-infra', display_name: 'Production Infra' }],
+    });
+    const el = document.getElementById('facet')!;
+
+    renderCollectionFacet(el);
+
+    expect(el.textContent).toContain('Production Infra');
+  });
+});