Update ChatDocumentHandler so RoomManger is no longer required for saving text

Update `ChatDocumentHandler` so `RoomManger` is no longer required for saving the text in the chatbar between room switches. This is achieved by allowing `ChatDocumentHandler` to get the correct `ChatBarChache` itself rather than having to have it passed from `ChatBar.qml`. This avoids any race conditions.

src/libneochat/enums/chatbartype.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2025 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#pragma once
+
+#include <QObject>
+#include <QQmlEngine>
+
+/**
+ * @class ChatBarType
+ *
+ * This class is designed to define the ChatBarType enumeration.
+ */
+class ChatBarType : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("")
+
+public:
+    /**
+     * @brief The type of chatbar.
+     */
+    enum Type {
+        Room = 0, /**< A standard room chatbar for creating new messages. */
+        Edit, /**< A chatbar for editing an existing message. */
+        Thread, /**< A chatbar for creating a new threaded message. */
+        None, /**< Undefined. */
+    };
+    Q_ENUM(Type);
+};