nextauth

# What does this PR do?


## Test Plan

llama_stack/ui/lib/auth.ts

@@ -0,0 +1,38 @@
+import { NextAuthOptions } from "next-auth";
+import GithubProvider from "next-auth/providers/github";
+
+export const authOptions: NextAuthOptions = {
+  providers: [
+    GithubProvider({
+      clientId: process.env.GITHUB_CLIENT_ID!,
+      clientSecret: process.env.GITHUB_CLIENT_SECRET!,
+      authorization: {
+        params: {
+          scope: "read:user user:email",
+        },
+      },
+    }),
+  ],
+  debug: process.env.NODE_ENV === "development",
+  callbacks: {
+    async jwt({ token, account }) {
+      // Persist the OAuth access_token to the token right after signin
+      if (account) {
+        token.accessToken = account.access_token;
+      }
+      return token;
+    },
+    async session({ session, token }) {
+      // Send properties to the client, like an access_token from a provider.
+      session.accessToken = token.accessToken as string;
+      return session;
+    },
+  },
+  pages: {
+    signIn: "/auth/signin",
+    error: "/auth/signin", // Redirect errors to our custom page
+  },
+  session: {
+    strategy: "jwt",
+  },
+};