test(e2e): isolate module mocks across harnesses

vitest.e2e.config.ts

@@ -21,7 +21,9 @@ export default defineConfig({
   ...base,
   test: {
     ...baseTest,
-    pool: "vmForks",
+    // vmForks reuses VM contexts in ways that can leak module state/mocks across
+    // files for our e2e harnesses. Use process forks for deterministic isolation.
+    pool: "forks",
     maxWorkers: e2eWorkers,
     silent: !verboseE2E,
     include: ["test/**/*.e2e.test.ts", "src/**/*.e2e.test.ts"],