feat: Add chat to editor view and refactor current openning

chat/ChatDocument.hpp

@@ -0,0 +1,27 @@
+// Copyright (C) 2024-2026 Petr Mironychev
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <coreplugin/idocument.h>
+
+namespace QodeAssist::Chat {
+
+// Backing document for a chat editor view. The chat persists itself through its own
+// autosave history file, so this document is purely a placeholder for the editor area
+// and never participates in Qt Creator's save infrastructure.
+class ChatDocument : public Core::IDocument
+{
+    Q_OBJECT
+
+public:
+    explicit ChatDocument(QObject *parent = nullptr);
+
+    QByteArray contents() const override;
+    Utils::Result<> setContents(const QByteArray &contents) override;
+    bool isModified() const override;
+    bool isSaveAsAllowed() const override;
+    bool shouldAutoSave() const override;
+};
+
+} // namespace QodeAssist::Chat