fix(test): hermetically exercise auth workflows

backend/test/windows-auth-storage.test.ts

@@ -46,9 +46,9 @@ function realChildBridge(
     bridge: factory({
       thtExecutable: pathStyle === "windows" ? "C:\\tht.exe" : launcher,
       spawnChild: (_executable, args, options) => spawn(launcher, [...args], options),
-      // Leave enough startup headroom for a real child under a busy CI host while retaining a
-      // sub-1.5-second bound from request start through final settlement.
-      deadlinesForTest: { timeoutMs: 750, terminationGraceMs: 50, finalSettlementMs: 500 },
+      // Keep this stricter than the five-second production timeout without assuming that a
+      // real Node child can always start within 750 ms on a busy shared runner.
+      deadlinesForTest: { timeoutMs: 2_000, terminationGraceMs: 50, finalSettlementMs: 500 },
       ...(mode === "stdin" ? {
         beforeInputForTest: async () => {
           await waitForMarker(marker, "stdin-closed");
@@ -585,6 +585,6 @@ describe("Windows auth-storage bridge", () => {
 
     await expect(outcome).resolves.toMatchObject({ message: "auth_session_store_invalid" });
     await waitForMarker(marker, "terminated");
-    expect(Date.now() - startedAt).toBeLessThan(1_500);
+    expect(Date.now() - startedAt).toBeLessThan(3_000);
   }, 5_000);
 });