fix(signal): guard hosted device linking

Co-authored-by: jesse-merhi <79823012+jesse-merhi@users.noreply.github.com>

extensions/signal/src/setup-surface.test.ts

@@ -186,6 +186,26 @@ describe("Signal hosted setup linking", () => {
     expect(result?.credentialValues?.signalNumber).toBe("+15555550125");
   });
 
+  it("rejects stale hosted authority before starting device linking", async () => {
+    const guardError = new Error("verified inference changed");
+    const beforePersistentEffect = vi.fn(async () => {
+      throw guardError;
+    });
+    const prompt = createPrompter();
+
+    await expect(
+      prepareSignal({
+        prompter: prompt.prompter,
+        beforePersistentEffect,
+      }),
+    ).rejects.toBe(guardError);
+
+    expect(beforePersistentEffect).toHaveBeenCalledOnce();
+    expect(mocks.spawnDaemon).not.toHaveBeenCalled();
+    expect(mocks.rpc).not.toHaveBeenCalled();
+    expect(prompt.qrCode).not.toHaveBeenCalled();
+  });
+
   it.each([
     { label: "without QR support", includeSignal: true, includeQr: false, cfg: {} },
     { label: "without hosted cancellation", includeSignal: false, includeQr: true, cfg: {} },

extensions/signal/src/setup-surface.ts

@@ -112,7 +112,7 @@ async function prepareManagedSignalLink(params: {
   accountId: string;
   runtime: RuntimeEnv;
   prompter: WizardPrompter;
-  options?: { signal?: AbortSignal };
+  options?: { signal?: AbortSignal; beforePersistentEffect?: () => Promise<void> };
   cliPath: string;
 }): Promise<string | undefined> {
   const signal = params.options?.signal;
@@ -133,6 +133,7 @@ async function prepareManagedSignalLink(params: {
     return undefined;
   }
 
+  await params.options?.beforePersistentEffect?.();
   signal.throwIfAborted();
   const lifecycle = createSignalDaemonLifecycle({ abortSignal: signal });
   const onAbort = () => void lifecycle.stop();