Fix media cover image sizing in WatchList component

- Add explicit width (230px) and height (330px) to media cover images
- Apply object-cover class to maintain aspect ratio and prevent distortion
- Ensures uniform sizing across all media cover images in the watch list

This change improves visual consistency in the UI by standardizing the display dimensions of anime/manga cover images.

frontend/src/helperComponents/WatchList.svelte

@@ -58,7 +58,7 @@
                 }}
               >
                 <img
-                  class="rounded-lg"
+                  class="rounded-lg w-[230px] h-[330px] object-cover"
                   src={media.media.coverImage.large}
                   alt={media.media.title.english === ""
                     ? media.media.title.romaji