test: reset leaked cron fake timers

src/cron/service.test-harness.ts

@@ -73,6 +73,10 @@ export function installCronTestHooks(options: {
 }) {
   beforeEach(() => {
     vi.useFakeTimers();
+    // Shared unit-thread workers run with isolate disabled, so leaked cron
+    // timers from a previous file can still sit in the fake-timer queue.
+    // Clear them before advancing time in the next test file.
+    vi.clearAllTimers();
     vi.setSystemTime(new Date(options.baseTimeIso ?? "2025-12-13T00:00:00.000Z"));
     options.logger.debug.mockClear();
     options.logger.info.mockClear();
@@ -81,6 +85,7 @@ export function installCronTestHooks(options: {
   });
 
   afterEach(() => {
+    vi.clearAllTimers();
     vi.useRealTimers();
   });
 }