feat: complete MVP foundation auth and dashboard

lib/proxy-auth.ts

@@ -0,0 +1,11 @@
+import { MOCK_SESSION_COOKIE_VALUE } from "./mock-auth";
+
+export function shouldRedirectDashboardRequest(
+  pathname: string,
+  sessionCookieValue: string | undefined,
+) {
+  return (
+    pathname.startsWith("/dashboard") &&
+    sessionCookieValue !== MOCK_SESSION_COOKIE_VALUE
+  );
+}