fix(desktop): isolate gateway HMR survivor across vitest cases

Vitest keeps import.meta.hot truthy, so boot-effect cleanup parks the
open socket; drain it between cases so the next test boots fresh.

apps/desktop/src/app/gateway/hooks/use-gateway-boot.test.tsx

@@ -4,6 +4,7 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { $desktopBoot } from '@/store/boot'
 import { $gatewayState } from '@/store/session'
 
+import { takeGatewaySurvivor } from './gateway-hmr-survivor'
 import { useGatewayBoot } from './use-gateway-boot'
 
 // End-to-end-ish repro of the "remote VPS → stuck on CONNECTING, no Settings"
@@ -131,6 +132,15 @@ function Harness({
 const originalWebSocket = globalThis.WebSocket
 
 beforeEach(() => {
+  // Drop any parked gateway left by a prior file/case (globalThis slot).
+  const leftover = takeGatewaySurvivor()
+  if (leftover) {
+    try {
+      leftover.gateway.close()
+    } catch {
+      // ignore
+    }
+  }
   vi.useFakeTimers()
   FakeWebSocket.mode = 'open'
   FakeWebSocket.instances = []
@@ -152,6 +162,17 @@ beforeEach(() => {
 
 afterEach(() => {
   cleanup()
+  // Vitest keeps import.meta.hot truthy, so the boot effect's cleanup parks an
+  // open gateway instead of tearing it down (the real HMR path). Drain + close
+  // that survivor so the next test boots a fresh socket instead of adoptBoot().
+  const survivor = takeGatewaySurvivor()
+  if (survivor) {
+    try {
+      survivor.gateway.close()
+    } catch {
+      // ignore
+    }
+  }
   vi.useRealTimers()
   ;(globalThis as { WebSocket: unknown }).WebSocket = originalWebSocket
   delete (window as { hermesDesktop?: unknown }).hermesDesktop