Add name field to share feature and require at least one item selection.

- Add name field to ShareCreateForm and ShareEditForm
- Add name column to SharesTable
- Update API routes to handle name field
- Require at least one item to be selected before saving
- Display parameters in responsive 3-column grid in edit form

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/(main)/websites/[websiteId]/settings/SharesTable.tsx

@@ -18,6 +18,9 @@ export function SharesTable(props: DataTableProps) {
 
   return (
     <DataTable {...props}>
+      <DataColumn id="name" label={formatMessage(labels.name)}>
+        {({ name }: any) => name}
+      </DataColumn>
       <DataColumn id="slug" label={formatMessage(labels.shareUrl)}>
         {({ slug }: any) => {
           const url = getUrl(slug);