ci: shard windows tests and fix event listener leaks (#18670)

packages/core/test-setup.ts

@@ -10,11 +10,19 @@ if (process.env.NO_COLOR !== undefined) {
 }
 
 import { setSimulate429 } from './src/utils/testUtils.js';
-import { vi } from 'vitest';
+import { vi, afterEach } from 'vitest';
+import { coreEvents } from './src/utils/events.js';
+
+// Increase max listeners to avoid warnings in large test suites
+coreEvents.setMaxListeners(100);
 
 // Disable 429 simulation globally for all tests
 setSimulate429(false);
 
+afterEach(() => {
+  vi.unstubAllEnvs();
+});
+
 // Default mocks for Storage and ProjectRegistry to prevent disk access in most tests.
 // These can be overridden in specific tests using vi.unmock().
 

packages/core/vitest.config.ts

@@ -9,8 +9,9 @@ import { defineConfig } from 'vitest/config';
 export default defineConfig({
   test: {
     reporters: ['default', 'junit'],
-    timeout: 30000,
-    hookTimeout: 30000,
+    testTimeout: 60000,
+    hookTimeout: 60000,
+    pool: 'forks',
     silent: true,
     setupFiles: ['./test-setup.ts'],
     outputFile: {
@@ -32,8 +33,8 @@ export default defineConfig({
     },
     poolOptions: {
       threads: {
-        minThreads: 8,
-        maxThreads: 16,
+        minThreads: 1,
+        maxThreads: 4,
       },
     },
   },