test(perf): run memory lane on thread pool

extensions/memory-core/src/dreaming-narrative.ts

@@ -322,7 +322,7 @@ export function extractNarrativeText(messages: unknown[]): string | null {
 
 export function formatNarrativeDate(epochMs: number, timezone?: string): string {
   const opts: Intl.DateTimeFormatOptions = {
-    timeZone: timezone,
+    timeZone: timezone ?? process.env.TZ,
     year: "numeric",
     month: "long",
     day: "numeric",

test/vitest-scoped-config.test.ts

@@ -321,7 +321,7 @@ describe("scoped vitest configs", () => {
       expect(normalizeConfigPath(config.test?.runner)).toBe("test/non-isolated-runner.ts");
     }
 
-    expect(defaultCommandsConfig.test?.pool).toBe("forks");
+    expect(defaultCommandsConfig.test?.pool).toBe("threads");
     expect(defaultCommandsConfig.test?.isolate).toBe(false);
     expect(normalizeConfigPath(defaultCommandsConfig.test?.runner)).toBe(
       "test/non-isolated-runner.ts",

test/vitest/vitest.extension-memory.config.ts

@@ -18,7 +18,6 @@ export function createExtensionMemoryVitestConfig(
       dir: "extensions",
       env,
       name: "extension-memory",
-      pool: "forks",
       passWithNoTests: true,
       setupFiles: ["test/setup.extensions.ts"],
     },