feat(companion): add heartbeat loop getState snapshot

src/companion/heartbeatLoop.test.ts

@@ -191,5 +191,10 @@ describe('CompanionHeartbeatLoop', () => {
     await loop.tickNow();
     expect(publishHeartbeat).toHaveBeenCalledTimes(1);
     expect(loop.running).toBe(false);
+    expect(loop.getState()).toEqual({
+      running: false,
+      failureCount: 0,
+      lastFailure: null,
+    });
   });
 });