test(hygiene): close every brain the integration suite creates

Each file opened a Brainy in beforeAll/beforeEach (or a single it()) and
never closed it. related-verb-array.test.ts and vfs-containment-batched.test.ts
were real bugs: their afterAll discarded the brain with `brain = null as any`
without ever calling close() first.

tests/integration/vfs-debug.test.ts

@@ -9,9 +9,10 @@ import * as XLSX from 'xlsx'
 describe('VFS Debug', () => {
   it('minimal VFS writeFile test', async () => {
     const brain = new Brainy({ requireSubtype: false, storage: { type: 'memory' } })
-    await brain.init()
+    try {
+      await brain.init()
 
-    console.log('✅ Brain initialized')
+      console.log('✅ Brain initialized')
 
     // Get VFS and initialize
     const vfs = brain.vfs
@@ -77,5 +78,8 @@ describe('VFS Debug', () => {
     // THE REAL TEST: Can we query VFS?
     expect(children.length).toBeGreaterThan(0)
     expect(rootContents.length).toBeGreaterThan(0)
+    } finally {
+      await brain.close()
+    }
   })
 })