test(e2e/agents): add shared _helpers (fake JWT + auth cookie)

useAuthorized requires an unexpired JWT in the `token` cookie before it
renders. We mint an unsigned 1-hour token here — jwt-decode never
verifies the signature, so any structurally valid base64 payload works.
Helper plus an AGENTS_DEV_URL constant (overridable via env).

ui/litellm-dashboard/e2e_tests/tests/agents/_helpers.ts

@@ -0,0 +1,66 @@
+/**
+ * Shared helpers for the cloud-agents Playwright suite.
+ *
+ * The dashboard's app router routes (/agents/...) only render under
+ * `next dev`, not under the proxy's static export. These tests therefore
+ * target http://localhost:3000 directly and run against the mock provider
+ * (NEXT_PUBLIC_USE_MOCK_AGENTS=true) so they're deterministic without
+ * Epic A merged.
+ *
+ * useAuthorized() requires a valid (unexpired) JWT in the `token` cookie
+ * before it'll render the dashboard. We mint a 1-hour HS-style fake here —
+ * client-side jwt-decode never verifies the signature, so any structurally
+ * valid base64 payload works.
+ */
+import type { Page } from "@playwright/test";
+
+export const AGENTS_DEV_URL = process.env.AGENTS_DEV_URL ?? "http://localhost:3000";
+
+function base64url(input: string): string {
+  return Buffer.from(input).toString("base64").replace(/=+$/g, "").replace(/\+/g, "-").replace(/\//g, "_");
+}
+
+/**
+ * Build a fake JWT with `key` (used as accessToken) and an exp 1 hour out.
+ * Signature is the literal string "fake" — jwt-decode ignores it.
+ */
+export function buildFakeToken(): string {
+  const header = base64url(JSON.stringify({ alg: "none", typ: "JWT" }));
+  const payload = base64url(
+    JSON.stringify({
+      key: "sk-mock",
+      user_id: "e2e-mock-user",
+      user_email: "e2e@test.local",
+      user_role: "proxy_admin",
+      exp: Math.floor(Date.now() / 1000) + 3600,
+    }),
+  );
+  return `${header}.${payload}.fake`;
+}
+
+/**
+ * Inject the fake token cookie for localhost:3000 so useAuthorized() doesn't
+ * redirect to /ui/login. Call before any page.goto() in the agents suite.
+ */
+export async function authenticateAgentsPage(page: Page): Promise<void> {
+  const url = new URL(AGENTS_DEV_URL);
+  await page.context().addCookies([
+    {
+      name: "token",
+      value: buildFakeToken(),
+      domain: url.hostname,
+      path: "/",
+      sameSite: "Lax",
+    },
+  ]);
+}
+
+/**
+ * Wait for the mock client to settle and the agents table to render.
+ * The mock provider resolves immediately, but React still has to flush.
+ */
+export async function gotoAgentsList(page: Page): Promise<void> {
+  await authenticateAgentsPage(page);
+  await page.goto(`${AGENTS_DEV_URL}/agents`);
+  await page.getByTestId("agents-table").waitFor({ state: "visible" });
+}