Add how many rooms you have in common to the user detail dialog

Eventually this will be expanded into an actual list you can look
through, but this can at least give you an idea the
number of rooms this user shares with you. If the user doesn't share any
rooms with you (e.g. they left) then the label is hidden.

src/models/commonroomsmodel.cpp

@@ -0,0 +1,74 @@
+// SPDX-FileCopyrightText: 2025 Joshua Goins <josh@redstrate.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "commonroomsmodel.h"
+#include "jobs/neochatgetcommonroomsjob.h"
+
+#include <QGuiApplication>
+
+using namespace Quotient;
+
+CommonRoomsModel::CommonRoomsModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+}
+
+NeoChatConnection *CommonRoomsModel::connection() const
+{
+    return m_connection;
+}
+
+void CommonRoomsModel::setConnection(NeoChatConnection *connection)
+{
+    m_connection = connection;
+    Q_EMIT connectionChanged();
+    reload();
+}
+
+QString CommonRoomsModel::userId() const
+{
+    return m_userId;
+}
+
+void CommonRoomsModel::setUserId(const QString &userId)
+{
+    m_userId = userId;
+    Q_EMIT userIdChanged();
+    reload();
+}
+
+QVariant CommonRoomsModel::data(const QModelIndex &index, int roleName) const
+{
+    Q_UNUSED(index)
+    Q_UNUSED(roleName)
+    return {};
+}
+
+int CommonRoomsModel::rowCount(const QModelIndex &parent) const
+{
+    Q_UNUSED(parent)
+    return m_commonRooms.size();
+}
+
+void CommonRoomsModel::reload()
+{
+    if (!m_connection || m_userId.isEmpty()) {
+        return;
+    }
+
+    if (!m_connection->canCheckMutualRooms()) {
+        return;
+    }
+
+    m_connection->callApi<NeochatGetCommonRoomsJob>(m_userId).then([this](const auto job) {
+        const auto &replyData = job->jsonData();
+        beginResetModel();
+        for (const auto &roomId : replyData[u"joined"_s].toArray()) {
+            m_commonRooms.push_back(roomId.toString());
+        }
+        endResetModel();
+        Q_EMIT countChanged();
+    });
+}
+
+#include "moc_commonroomsmodel.cpp"