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>

Core/Services/NoteNamingService.cs

@@ -8,6 +8,7 @@ public class NoteNamingService : INoteNamingService
 {
     private const string PageNotePrefix = "#";
     private const string MeetingNotePrefix = "#Meeting Notes";
+    private const string StudentNotePrefix = "#Student:";
 
     /// <inheritdoc/>
     public string GetMeetingNoteTitle(DateTime meetingDate)
@@ -47,4 +48,26 @@ public class NoteNamingService : INoteNamingService
 
         return noteTitle.StartsWith(MeetingNotePrefix, StringComparison.Ordinal);
     }
+
+    /// <inheritdoc/>
+    public string GetStudentNoteTitle(int studentId) => $"{StudentNotePrefix}{studentId}";
+
+    /// <inheritdoc/>
+    public bool IsStudentNote(string? noteTitle)
+    {
+        if (string.IsNullOrWhiteSpace(noteTitle))
+            return false;
+
+        return noteTitle.StartsWith(StudentNotePrefix, StringComparison.Ordinal);
+    }
+
+    /// <inheritdoc/>
+    public bool TryParseStudentNoteId(string? noteTitle, out int studentId)
+    {
+        studentId = 0;
+        if (!IsStudentNote(noteTitle))
+            return false;
+
+        return int.TryParse(noteTitle.AsSpan(StudentNotePrefix.Length), out studentId);
+    }
 }