test(core): update main test setup and core tests

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

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

test-setup.ts

@@ -1,10 +1,57 @@
-import { beforeEach } from "bun:test"
+import { afterEach, beforeEach, mock } from "bun:test"
+import { rmSync } from "node:fs"
 import { _resetForTesting as resetClaudeSessionState } from "./src/features/claude-code-session-state/state"
+import { _resetTaskToastManagerForTesting as resetTaskToastManager } from "./src/features/task-toast-manager/manager"
 import { _resetForTesting as resetModelFallbackState } from "./src/hooks/model-fallback/hook"
 import { _resetMemCacheForTesting as resetConnectedProvidersCache } from "./src/shared/connected-providers-cache"
+import { getOmoOpenCodeCacheDir } from "./src/shared/data-path"
+import { installModuleMockLifecycle } from "./src/testing/module-mock-lifecycle"
+
+const { restoreModuleMocks } = installModuleMockLifecycle(mock)
+let environmentSnapshot: NodeJS.ProcessEnv = { ...process.env }
+let workingDirectorySnapshot = process.cwd()
+
+function cleanupOmoCacheDir(cacheDir: string): void {
+  rmSync(cacheDir, { recursive: true, force: true })
+}
 
 beforeEach(() => {
+  environmentSnapshot = { ...process.env }
+  workingDirectorySnapshot = process.cwd()
+  process.env.OMO_DISABLE_POSTHOG = "true"
+  cleanupOmoCacheDir(getOmoOpenCodeCacheDir())
   resetClaudeSessionState()
+  resetTaskToastManager()
   resetModelFallbackState()
   resetConnectedProvidersCache()
 })
+
+afterEach(() => {
+  const currentCacheDir = getOmoOpenCodeCacheDir()
+
+  for (const key of Object.keys(process.env)) {
+    if (!(key in environmentSnapshot)) {
+      delete process.env[key]
+    }
+  }
+
+  for (const [key, value] of Object.entries(environmentSnapshot)) {
+    if (value === undefined) {
+      delete process.env[key]
+      continue
+    }
+
+    process.env[key] = value
+  }
+
+  if (process.cwd() !== workingDirectorySnapshot) {
+    process.chdir(workingDirectorySnapshot)
+  }
+
+  cleanupOmoCacheDir(currentCacheDir)
+  cleanupOmoCacheDir(getOmoOpenCodeCacheDir())
+  resetTaskToastManager()
+  resetConnectedProvidersCache()
+  mock.restore()
+  restoreModuleMocks()
+})