8065c589bc
Replaced direct file links with a JavaScript-based viewer (`openAttachmentViewer`) and added a DevExtreme Popup (`attachment-viewer-popup`) for displaying attachments in a modal dialog. The viewer supports PDFs (via PDF.js), XML (with CodeMirror syntax highlighting), plain text, images, and provides a fallback for unsupported file types. Dynamically load CodeMirror for XML files and handle errors gracefully when loading file content. Added `onAttachmentPopupHiding` to clear popup content on close. Updated `ViewAttachmentModel` to return text/XML content directly for AJAX requests, improving frontend performance and enabling dynamic content loading.