Add sign-out action and button to dashboard placeholder

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dcl10

frontend/app/actions.ts

@@ -1,6 +1,6 @@
 "use server";
 
-import { signIn } from "@/auth";
+import { signIn, signOut } from "@/auth";
 
 /**
  * Initiates the Keycloak OAuth flow via a server action.
@@ -20,3 +20,8 @@ export async function signInWithKeycloak() {
 export async function signUpWithKeycloak() {
   await signIn("keycloak", { redirectTo: "/dashboard" }, { prompt: "create" });
 }
+
+/** Signs the user out and redirects to the landing page. */
+export async function signOutFromKeycloak() {
+  await signOut({ redirectTo: "/" });
+}

frontend/app/dashboard/page.tsx

@@ -1,5 +1,6 @@
 import { redirect } from "next/navigation";
 
+import { signOutFromKeycloak } from "@/app/actions";
 import { getSession } from "@/lib/auth";
 
 export default async function DashboardPage() {
@@ -11,9 +12,17 @@ export default async function DashboardPage() {
       <h1 className="text-3xl font-bold tracking-[-0.025em] text-ink mb-3">
         Your project dashboard
       </h1>
-      <p className="text-[15px] text-ink-soft">
+      <p className="text-[15px] text-ink-soft mb-8">
         Dashboard functionality coming soon.
       </p>
+      <form action={signOutFromKeycloak}>
+        <button
+          type="submit"
+          className="inline-flex items-center gap-2 font-sans font-medium tracking-[-0.005em] rounded-sm px-[16px] py-[9px] text-[14px] bg-paper text-ink border border-[var(--border-strong)] hover:bg-portland-stone transition-colors duration-[120ms] cursor-pointer"
+        >
+          Sign out
+        </button>
+      </form>
     </main>
   );
 }