feat: Add temp file storage for chat (#279)

* fix: Add signature to chat history
* feat: Add file storage for chat

ChatView/ChatFileManager.hpp

@@ -0,0 +1,59 @@
+/* 
+ * Copyright (C) 2024-2025 Petr Mironychev
+ *
+ * This file is part of QodeAssist.
+ *
+ * QodeAssist is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QodeAssist is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QodeAssist. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QObject>
+#include <QString>
+#include <QStringList>
+#include <QMap>
+
+namespace QodeAssist::Chat {
+
+class ChatFileManager : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit ChatFileManager(QObject *parent = nullptr);
+    ~ChatFileManager();
+
+    QStringList processDroppedFiles(const QStringList &filePaths);
+    void setChatFilePath(const QString &chatFilePath);
+    QString chatFilePath() const;
+    void clearIntermediateStorage();
+
+    static bool isFileAccessible(const QString &filePath);
+    static void cleanupGlobalIntermediateStorage();
+
+signals:
+    void fileOperationFailed(const QString &error);
+    void fileCopiedToStorage(const QString &originalPath, const QString &newPath);
+
+private:
+    QString copyToIntermediateStorage(const QString &filePath);
+    QString getIntermediateStorageDir();
+    QString generateIntermediateFileName(const QString &originalPath);
+
+    QString m_chatFilePath;
+    QString m_intermediateStorageDir;
+};
+
+} // namespace QodeAssist::Chat
+