Move remaining code to app module

There's still some stuff that could potentially go elsewhere but I think it's enough for now.

src/app/models/commonroomsmodel.cpp

@@ -0,0 +1,79 @@
+// 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;
+    }
+
+    // Checking if you have mutual rooms with yourself doesn't make sense and servers reject it too
+    if (m_connection->userId() == m_userId) {
+        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"