fix(ui): replace form with div in link popover to prevent unintended submit behavior

- swap `<form>` wrapper for `<div>` to avoid native form submission
- add `onKeyDown` handler on input to trigger submit on Enter key
- change button type from `submit` to `button` with explicit `onClick` handler

src/shared/components/BlockEditor/inline/Toolbar.client.js

@@ -175,8 +175,7 @@ export default function InlineToolbar({ rect, activeMarks, onToggleMark, onClear
         />
       )}
       {popover === 'link' && (
-        <form
+        <div
-          onSubmit={handleLinkSubmit}
           className="absolute top-full left-0 mt-1 flex flex-col gap-1.5 rounded-lg border border-neutral-200 dark:border-neutral-700 bg-white dark:bg-neutral-900 shadow-md px-2 py-1.5"
         >
           <div className="flex items-center gap-1">
@@ -186,10 +185,12 @@ export default function InlineToolbar({ rect, activeMarks, onToggleMark, onClear
               placeholder="https://..."
               value={linkUrl}
               onChange={(e) => setLinkUrl(e.target.value)}
+              onKeyDown={(e) => { if (e.key === 'Enter') { e.preventDefault(); handleLinkSubmit(e); } }}
               className="w-56 px-2 py-1 text-sm rounded border border-neutral-200 dark:border-neutral-700 bg-white dark:bg-neutral-900 text-neutral-900 dark:text-white outline-none focus:border-blue-500"
             />
             <button
-              type="submit"
+              type="button"
+              onClick={handleLinkSubmit}
               className="px-2 py-1 text-xs rounded bg-blue-600 hover:bg-blue-700 text-white"
             >
               OK
@@ -214,7 +215,7 @@ export default function InlineToolbar({ rect, activeMarks, onToggleMark, onClear
             />
             Ouvrir dans un nouvel onglet
           </label>
-        </form>
+        </div>
       )}
     </div>
   );