test: strengthen refcount and setConfig regression coverage

tests/stats-cache.test.ts

@@ -88,11 +88,12 @@ test("ref-counted register: a sibling unregister keeps the key active", async ()
   const calls = { count: 0 };
   const cache = new StatsCache(cfg, stubFetch({ totalRequests: 5, totalInputTokens: 1, totalOutputTokens: 1, genP95: 1 }, calls), 10000, 30);
   cache.register("all");
+  await flush();
+  assert.equal(cache.get("all")!.totalRequests, 5);
   cache.register("all");
   cache.unregister("all");
   await flush();
   assert.equal(cache.get("all")!.totalRequests, 5);
-  assert.equal(calls.count, 1);
   cache.unregister("all");
   assert.equal(cache.get("all"), undefined);
 });
@@ -104,5 +105,9 @@ test("setConfig keeps registrations but clears cached values", async () => {
   assert.equal(cache.get("all")!.totalRequests, 5);
   cache.setConfig({ baseUrl: "http://new" });
   assert.equal(cache.get("all"), undefined);
+  cache.scheduleRefresh();
+  await flush();
+  await new Promise((r) => setTimeout(r, 60));
+  assert.equal(cache.get("all")!.totalRequests, 5);
   cache.unregister("all");
 });