diff --git a/web/src/components/dashboard/customizer/sections/__tests__/TemplateGallerySection.test.tsx b/web/src/components/dashboard/customizer/sections/__tests__/TemplateGallerySection.test.tsx
index b3e448921e..875bc7aa80 100644
--- a/web/src/components/dashboard/customizer/sections/__tests__/TemplateGallerySection.test.tsx
+++ b/web/src/components/dashboard/customizer/sections/__tests__/TemplateGallerySection.test.tsx
@@ -11,8 +11,8 @@ vi.mock('react-i18next', () => ({
 }))
 
 vi.mock('lucide-react', () => ({
-  Check: (props: Record<string, unknown>) => <span data-testid="check-icon" {...props} />,
-  Search: (props: Record<string, unknown>) => <span data-testid="search-icon" {...props} />,
+  Check: () => <span data-testid="check-icon" />,
+  Search: () => <span data-testid="search-icon" />,
 }))
 
 vi.mock('../../../../../lib/formatCardTitle', () => ({
@@ -20,7 +20,7 @@ vi.mock('../../../../../lib/formatCardTitle', () => ({
 }))
 
 vi.mock('../../../../../lib/icons', () => ({
-  getIcon: () => (props: Record<string, unknown>) => <span data-testid="cat-icon" {...props} />,
+  getIcon: () => () => <span data-testid="cat-icon" />,
 }))
 
 vi.mock('../../../templates', () => ({
diff --git a/web/src/hooks/useMissions.provider.tsx b/web/src/hooks/useMissions.provider.tsx
index ffae53abc3..5156a9c991 100644
--- a/web/src/hooks/useMissions.provider.tsx
+++ b/web/src/hooks/useMissions.provider.tsx
@@ -399,7 +399,7 @@ export function useMissions() {
   const context = useContext(MissionContext)
   if (!context) {
     if (import.meta.env.DEV) {
-      logger.warn('useMissions was called outside MissionProvider — returning safe fallback')
+      console.warn('useMissions was called outside MissionProvider — returning safe fallback')
     }
     return MISSIONS_FALLBACK
   }
diff --git a/web/src/test/setup.ts b/web/src/test/setup.ts
index 639630a4d2..0ec51be87d 100644
--- a/web/src/test/setup.ts
+++ b/web/src/test/setup.ts
@@ -226,6 +226,7 @@ afterEach(() => {
     window.sessionStorage?.clear()
   }
   vi.unstubAllEnvs()
+  vi.restoreAllMocks() // Restore mocks but preserve global stubs (e.g., localStorage) (#20007)
   vi.clearAllMocks()
 })
 
@@ -233,9 +234,8 @@ afterEach(() => {
 // In vitest 4.x with pool:'forks'/isolate:false and maxWorkers:1 (CI), all test
 // files in a shard share one worker process, so vi.stubGlobal() calls in one
 // file's beforeAll leak into subsequent files.
-// afterAll in setupFiles runs once per worker (end of shard), not once per file,
-// so this only partially mitigates contamination — see issue #20256 for the
-// full architectural fix (pool:'forks', isolate:true).
+// afterAll in setupFiles runs once per worker (end of shard), not once per file.
+// Belt-and-suspenders: primary cleanup now happens in afterEach above (#20007).
 afterAll(() => {
   vi.unstubAllGlobals()
 })
diff --git a/web/vite.config.ts b/web/vite.config.ts
index d86d5cde26..ee95acf167 100644
--- a/web/vite.config.ts
+++ b/web/vite.config.ts
@@ -319,9 +319,9 @@ export default defineConfig(({ mode }) => ({
     // isolate: true ensures each test file runs in its own subprocess with a clean global environment,
     // preventing vi.stubGlobal() cross-contamination between files (#20256)
     isolate: true,
-    // poolOptions.forks removed — deprecated in Vitest 4 (#5860).
-    // maxWorkers/minWorkers above handle fork limits; teardownTimeout
-    // above handles worker termination timeout.
+    // CI: use threads pool instead of forks to prevent OOM from subprocess spawn storm (#20007)
+    // Threads share memory, no fork overhead. Local dev uses default (forks) for stronger isolation.
+    pool: process.env.CI ? 'threads' : undefined,
     coverage: {
       provider: 'v8',
       // Disable coverage.all to prevent force-importing source files that trigger