Fix terminal auth fallback navigation

frontend/components/dashboard/scan-terminal/ProductAccessRequired.tsx

@@ -137,25 +137,25 @@ function UnauthenticatedGate({
                 ? "The weather terminal is for verified subscribers only."
                 : "天气决策台仅对已验证的付费用户开放。"}
             </p>
-            <Link
+            <a
               href="/auth/login?next=%2Fterminal"
               className="mt-6 flex items-center justify-center gap-2 rounded-xl bg-slate-900 py-3 text-sm font-black text-white transition hover:bg-slate-700"
             >
               <LogIn size={15} />
               {isEn ? "Log in" : "登录"}
-            </Link>
+            </a>
-            <Link
+            <a
               href="/auth/login?next=%2Fterminal&mode=signup"
               className="mt-3 flex items-center justify-center gap-2 rounded-xl border border-slate-300 py-3 text-sm font-black text-slate-700 transition hover:bg-slate-50"
             >
               {isEn ? "Create an account" : "注册账号"}
-            </Link>
+            </a>
-            <Link
+            <a
               href="/"
               className="mt-4 block text-xs text-slate-400 hover:text-slate-700 transition-colors"
             >
               {isEn ? "← Learn about PolyWeather" : "← 了解 PolyWeather"}
-            </Link>
+            </a>
           </div>
         </section>
       </main>

frontend/components/dashboard/scan-terminal/__tests__/productAccessRequired.test.ts

@@ -0,0 +1,40 @@
+import fs from "node:fs";
+import path from "node:path";
+
+function assert(condition: unknown, message: string) {
+  if (!condition) throw new Error(message);
+}
+
+export function runTests() {
+  const source = fs.readFileSync(
+    path.join(
+      process.cwd(),
+      "components",
+      "dashboard",
+      "scan-terminal",
+      "ProductAccessRequired.tsx",
+    ),
+    "utf8",
+  );
+  const unauthenticatedGate = source.slice(
+    source.indexOf("function UnauthenticatedGate"),
+    source.indexOf("export function ProductAccessRequired"),
+  );
+
+  const accessCard = unauthenticatedGate.slice(
+    unauthenticatedGate.indexOf('<section className="grid flex-1'),
+  );
+
+  assert(
+    !accessCard.includes("<Link"),
+    "signed-out terminal gate must use native anchors so stale client router state cannot block login navigation",
+  );
+  assert(
+    accessCard.includes('href="/auth/login?next=%2Fterminal"') &&
+      accessCard.includes(
+        'href="/auth/login?next=%2Fterminal&mode=signup"',
+      ) &&
+      accessCard.includes('href="/"'),
+    "signed-out terminal gate must keep hard navigation targets for login, signup, and product overview",
+  );
+}