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/TestAttachmentsGui.cpp

@@ -0,0 +1,46 @@
+#include <QtTest>
+
+#include "TestAttachmentWidget.h"
+#include "TestEditEntryAttachmentsDialog.h"
+#include "TestImageAttachmentsView.h"
+#include "TestImageAttachmentsWidget.h"
+#include "TestPreviewEntryAttachmentsDialog.h"
+#include "TestTextAttachmentsEditWidget.h"
+#include "TestTextAttachmentsPreviewWidget.h"
+#include "TestTextAttachmentsWidget.h"
+
+#include <config-keepassx.h>
+#include <gui/Application.h>
+
+int main(int argc, char* argv[])
+{
+    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+    Application app(argc, argv);
+    app.setApplicationName("KeePassXC");
+    app.setApplicationVersion(KEEPASSXC_VERSION);
+    app.setQuitOnLastWindowClosed(false);
+    app.setAttribute(Qt::AA_Use96Dpi, true);
+    app.applyTheme();
+
+    TestPreviewEntryAttachmentsDialog previewDialogTest{};
+    TestEditEntryAttachmentsDialog editDialogTest{};
+    TestTextAttachmentsWidget textAttachmentsWidget{};
+    TestTextAttachmentsPreviewWidget textPreviewWidget{};
+    TestTextAttachmentsEditWidget textEditWidget{};
+    TestImageAttachmentsWidget imageWidget{};
+    TestImageAttachmentsView imageView{};
+    TestAttachmentsWidget attachmentWidget{};
+
+    int result = 0;
+    result |= QTest::qExec(&previewDialogTest, argc, argv);
+    result |= QTest::qExec(&editDialogTest, argc, argv);
+    result |= QTest::qExec(&textAttachmentsWidget, argc, argv);
+    result |= QTest::qExec(&textPreviewWidget, argc, argv);
+    result |= QTest::qExec(&textEditWidget, argc, argv);
+    result |= QTest::qExec(&imageWidget, argc, argv);
+    result |= QTest::qExec(&imageView, argc, argv);
+    result |= QTest::qExec(&attachmentWidget, argc, argv);
+
+    return result;
+}