Images cannot have links in the visual email editor

## Problem The Tiptap-based visual email editor strips anchor tags from images. When loading HTML like `<a href="..."><img src="..."></a>`, the editor drops the `<a>` wrapper, leaving a bare `<img>`. Clicking images shows no option to add a link. This makes it impossible to create clickable logos, thumbnails, or banner images in the visual editor — a basic requirement for email design. ## Expected behavior - Images wrapped in `<a>` tags in HTML should preserve their links when loaded into the editor - Clicking an image should show a link button in the toolbar - Users should be able to add, edit, and remove links from images ## Steps to reproduce 1. Open the visual email editor (template or campaign) 2. Switch to HTML mode and paste: `<a href="https://example.com"><img src="https://picsum.photos/200" /></a>` 3. Switch back to visual mode 4. Observe the image has lost its link 5. Click the image — no link option is available