feat: import leftover student fields into notes and show them on the roster

Store leftover CSV columns on hidden student notes, move catalog import to /events/import, and persist Students index columns from Chapter Settings.

Co-authored-by: Cursor <cursoragent@cursor.com>

WebApp/Components/Features/Events/Index.razor

@@ -4,6 +4,7 @@
 @using Microsoft.EntityFrameworkCore
 @using WebApp.Models
 @using WebApp.Components.Shared.Components
+@using WebApp.Authentication
 @inject AppDbContext Context
 @inject IDialogService DialogService
 @inject ISnackbar Snackbar
@@ -13,6 +14,11 @@
         <MudTooltip Text="Create New">
             <MudButton StartIcon="@Icons.Material.Filled.Create" Href="events/create" Variant="Variant.Filled" Color="Color.Primary">Create New</MudButton>
         </MudTooltip>
+        <AuthorizeView Roles="@AuthRoles.Administrator">
+            <MudTooltip Text="Add new catalog events from CSV. Existing names are skipped.">
+                <MudButton StartIcon="@Icons.Material.Filled.UploadFile" Href="/events/import" Variant="Variant.Outlined">Import</MudButton>
+            </MudTooltip>
+        </AuthorizeView>
         <MudTooltip Text="Printable Descriptions">
             <MudButton StartIcon="@Icons.Material.Filled.Print" Href="events/printout" Variant="Variant.Outlined">Printable Descriptions</MudButton>
         </MudTooltip>