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.h

@@ -0,0 +1,58 @@
+// SPDX-FileCopyrightText: 2025 Joshua Goins <josh@redstrate.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QAbstractListModel>
+#include <QQmlEngine>
+
+#include "neochatconnection.h"
+#include "neochatroom.h"
+
+#include <Quotient/events/roommessageevent.h>
+#include <Quotient/roommember.h>
+
+/**
+ * @brief Model to show the common or mutual rooms between you and another user.
+ */
+class CommonRoomsModel : public QAbstractListModel
+{
+    Q_OBJECT
+    QML_ELEMENT
+    Q_PROPERTY(NeoChatConnection *connection WRITE setConnection READ connection NOTIFY connectionChanged REQUIRED)
+    Q_PROPERTY(QString userId WRITE setUserId READ userId NOTIFY userIdChanged REQUIRED)
+    Q_PROPERTY(int count READ rowCount NOTIFY countChanged)
+
+public:
+    enum Roles {
+        TextRole = Qt::DisplayRole,
+        LongitudeRole,
+        LatitudeRole,
+        AssetRole,
+        AuthorRole,
+    };
+    Q_ENUM(Roles)
+
+    explicit CommonRoomsModel(QObject *parent = nullptr);
+
+    [[nodiscard]] NeoChatConnection *connection() const;
+    void setConnection(NeoChatConnection *connection);
+
+    [[nodiscard]] QString userId() const;
+    void setUserId(const QString &userId);
+
+    [[nodiscard]] QVariant data(const QModelIndex &index, int roleName) const override;
+    [[nodiscard]] Q_INVOKABLE int rowCount(const QModelIndex &parent = {}) const override;
+
+Q_SIGNALS:
+    void connectionChanged();
+    void userIdChanged();
+    void countChanged();
+
+private:
+    void reload();
+
+    QPointer<NeoChatConnection> m_connection;
+    QString m_userId;
+    QList<QString> m_commonRooms;
+};