fix(ci): resolve mock.module() cross-file leakage in test suite

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/background-agent/manager.test.ts

@@ -20,6 +20,7 @@ import { MIN_IDLE_TIME_MS } from "./constants"
 import { BackgroundManager } from "./manager"
 import { ConcurrencyManager } from "./concurrency"
 import { initTaskToastManager, _resetTaskToastManagerForTesting } from "../task-toast-manager/manager"
+mock.restore()
 
 
 const TASK_TTL_MS = 30 * 60 * 1000