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/Students/Edit.razor

@@ -52,6 +52,11 @@
                     </MudSelect>
                 </MudPaper>
             </MudItem>
+            <MudItem xs="12" sm="5">
+                <MudPaper Elevation="2" Class="pa-3 pa-md-6">
+                    <StudentNotePanel @ref="_notePanel" StudentId="Student.Id" />
+                </MudPaper>
+            </MudItem>
         </MudGrid>
 </EditForm>
 
@@ -73,6 +78,7 @@
     private FormChangeTracker? _formChangeTracker;
     private EditContext? _editContext;
     private List<string> _validationErrors = new();
+    private StudentNotePanel? _notePanel;
 
     protected override async Task OnInitializedAsync()
     {
@@ -120,6 +126,8 @@
         try
         {
             await Context.SaveChangesAsync();
+            if (_notePanel is not null)
+                await _notePanel.SaveAsync();
             Snackbar.Add($"Student '{Student!.FirstNameLastName}' saved successfully.", Severity.Success);
             _formChangeTracker?.AllowNavigation();
             NavigationManager.NavigateTo(ReturnUrl ?? "/students");