fix(disputed): add admin role + contact info in discussion modal

- request-discussion endpoint: add 'admin' to allowed roles
- Return rejector_email and rejector_role in the response
- Modal success state shows contact card with username, role, email link
  so the approving lead can immediately reach out to the rejecting lead

frontend/src/api/tests.ts

@@ -313,6 +313,8 @@ export async function requestDiscussion(testId: string): Promise<{
   status: string;
   message: string;
   rejector_username: string;
+  rejector_email: string | null;
+  rejector_role: string;
 }> {
   const { data } = await client.post(`/tests/${testId}/request-discussion`);
   return data;

frontend/src/components/test-detail/TestDetailHeader.tsx

@@ -87,11 +87,17 @@ export default function TestDetailHeader({
   const role = user?.role ?? "";
   const currentIdx = STATE_INDEX[test.state];
   const [showDiscussModal, setShowDiscussModal] = useState(false);
-  const [discussResult, setDiscussResult] = useState<string | null>(null);
+  const [discussResult, setDiscussResult] = useState<{
+    username: string; email: string | null; role: string;
+  } | null>(null);
 
   const discussMutation = useMutation({
     mutationFn: () => requestDiscussion(test.id),
-    onSuccess: (data) => setDiscussResult(data.rejector_username),
+    onSuccess: (data) => setDiscussResult({
+      username: data.rejector_username,
+      email: data.rejector_email,
+      role: data.rejector_role,
+    }),
   });
 
   const formatDate = (d: string | null) => {
@@ -544,16 +550,40 @@ export default function TestDetailHeader({
                 )}
               </div>
             ) : (
-              /* Success state */
-              <div className="px-6 py-8 text-center space-y-3">
-                <CheckCircle className="mx-auto h-12 w-12 text-green-400" />
-                <p className="text-lg font-semibold text-white">Discussion request sent</p>
-                <p className="text-sm text-gray-400">
-                  <strong className="text-white">{discussResult}</strong> has been notified
-                  that you are standing by your approval and want to discuss their rejection.
-                </p>
-                <p className="text-xs text-gray-500">
-                  Reach out directly via your team's communication channels to resolve this.
+              /* Success state with contact info */
+              <div className="px-6 py-6 space-y-4">
+                <div className="flex items-center gap-3">
+                  <CheckCircle className="h-8 w-8 shrink-0 text-green-400" />
+                  <div>
+                    <p className="text-base font-semibold text-white">Discussion request sent</p>
+                    <p className="text-xs text-gray-400">
+                      {discussResult?.role} has been notified that you want to discuss.
+                    </p>
+                  </div>
+                </div>
+
+                {/* Contact card */}
+                <div className="rounded-lg border border-amber-500/20 bg-amber-500/5 p-4 space-y-2">
+                  <p className="text-xs font-semibold uppercase tracking-wider text-amber-400">Contact details</p>
+                  <div className="flex items-center gap-2">
+                    <span className="text-sm font-medium text-white">{discussResult?.username}</span>
+                    <span className="rounded-full border border-gray-600 bg-gray-800 px-2 py-0.5 text-[10px] text-gray-400">
+                      {discussResult?.role}
+                    </span>
+                  </div>
+                  {discussResult?.email && (
+                    <a
+                      href={`mailto:${discussResult.email}`}
+                      className="flex items-center gap-1.5 text-xs text-cyan-400 hover:underline"
+                    >
+                      ✉ {discussResult.email}
+                    </a>
+                  )}
+                </div>
+
+                <p className="text-xs text-gray-500 leading-relaxed">
+                  Reach out directly via the contact above or your team's communication channels (Slack, Teams, etc.) to resolve the disagreement.
+                  The test will remain in <strong className="text-amber-400">Disputed</strong> state until one lead changes their vote.
                 </p>
               </div>
             )}