perf(test): avoid importing update-check in startup suite

src/infra/update-startup.test.ts

@@ -9,11 +9,23 @@ vi.mock("./openclaw-root.js", () => ({
 }));
 
 vi.mock("./update-check.js", async () => {
-  const actual = await vi.importActual<typeof import("./update-check.js")>("./update-check.js");
+  const parse = (value: string) => value.split(".").map((part) => Number.parseInt(part, 10));
+  const compareSemverStrings = (a: string, b: string) => {
+    const left = parse(a);
+    const right = parse(b);
+    for (let idx = 0; idx < 3; idx += 1) {
+      const l = left[idx] ?? 0;
+      const r = right[idx] ?? 0;
+      if (l !== r) {
+        return l < r ? -1 : 1;
+      }
+    }
+    return 0;
+  };
+
   return {
-    ...actual,
     checkUpdateStatus: vi.fn(),
-    fetchNpmTagVersion: vi.fn(),
+    compareSemverStrings,
     resolveNpmChannelTag: vi.fn(),
   };
 });