Refactor attachment handling system with enhanced UI (#12085)

* Renamed NewEntryAttachmentsDialog to EditEntryAttachmentsDialog for clarity.
* Introduced EditEntryAttachmentsDialog class to manage editing of existing attachments.
* Added functionality to preview attachments while editing them.
* Enhanced EntryAttachmentsModel with rowByKey method for better key management.
* Add image attachment support with zoom functionality.
* Add html and markdown detection.
* Improve button layout on the attachment section when editing an entry

tests/gui/attachments/TestTextAttachmentsWidget.h

@@ -0,0 +1,42 @@
+/*
+ *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program 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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <attachments/TextAttachmentsWidget.h>
+
+#include <QObject>
+#include <QScopedPointer>
+
+class TestTextAttachmentsWidget : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void initTestCase();
+
+    void testInitTextWidget();
+    void testTextReadWriteWidget();
+    void testTextReadWidget();
+    void testOpenPreviewButton();
+    void testPreviewTextChanged();
+    void testTextChanged();
+    void testTextChangedInReadOnlyMode();
+
+private:
+    QScopedPointer<TextAttachmentsWidget> m_textWidget;
+};