test(8.0): close brains in afterEach (count-sync, get-relations teardown)

Both suites removed their test directory without closing the brain, leaving the
writer-lock heartbeat + flush timers running into teardown and the next test.
Adds brain.close() before the rm.

Remaining failures in these files are separate, deeper issues (tracked in
.strategy): get-relations has one pagination assertion; count-sync is off-by-one
because a fresh brain carries one system/VFS-root noun that counts in
totalNounCount while find() excludes it — a counts-semantics decision.

tests/integration/count-synchronization.test.ts

@@ -34,6 +34,14 @@ describe('Count Synchronization (Bug Fix v4.1.2)', () => {
   })
 
   afterEach(async () => {
+    // Close the brain first so its writer-lock heartbeat + flush timers stop
+    // before the directory is removed — otherwise they race teardown and bleed
+    // state into the next test.
+    try {
+      await brain?.close()
+    } catch {
+      // Best-effort teardown.
+    }
     // Clean up test directory
     try {
       await fs.rm(testPath, { recursive: true, force: true })

tests/integration/get-relations-fix.test.ts

@@ -33,6 +33,14 @@ describe('related() call patterns', () => {
   })
 
   afterEach(async () => {
+    // Close the brain first so its writer-lock heartbeat + flush timers stop
+    // before the directory is removed — otherwise they race teardown and bleed
+    // state into the next test.
+    try {
+      await brain?.close()
+    } catch {
+      // Best-effort teardown.
+    }
     // Clean up test directory
     try {
       await fs.rm(testPath, { recursive: true, force: true })