[chore:] error-count overview after crafting courses

crafter.cs

@@ -166,14 +166,24 @@ public class CourseCrafter
     
     public static string GenerateStatistics()
     {
+        var settings = Settings.Instance;
+        var students = settings.Students;
+
         if (GeneratedCourses == null || GeneratedCourses.Count == 0)
             return "Keine Kurse generiert.";
 
+        int semesterCount = students
+            .Where(s => s.Result != null)
+            .Select(s => s.Result!.Count)
+            .DefaultIfEmpty(0)
+            .Max();
+
         var sb = new System.Text.StringBuilder();
 
         sb.AppendLine($"Anzahl generierter Kurse: {GeneratedCourses.Count}");
         sb.AppendLine("Übersicht:");
 
+        // ===== Kursübersicht =====
         var grouped = GeneratedCourses
             .GroupBy(g => new { g.Semester, g.Instance.Sport.Name })
             .OrderBy(g => g.Key.Semester)
@@ -183,21 +193,35 @@ public class CourseCrafter
         {
             int counter = 1;
 
-            foreach (var course in group)
+            foreach (var entry in group)
             {
-                string number = counter.ToString("D2");
                 int semester = group.Key.Semester + 1;
                 string sportName = group.Key.Name;
-                int studentCount = course.Instance.Students.Count;
+                string number = counter.ToString("D2");
+                int count = entry.Instance.Students.Count;
 
                 sb.AppendLine(
-                    $"Semester {semester}: {sportName} {number}: {studentCount} Schüler*innen"
+                    $"Semester {semester}: {sportName} {number}: {count} Schüler*innen"
                 );
 
                 counter++;
             }
         }
 
+        sb.AppendLine();
+        sb.AppendLine("Fehlerübersicht:");
+
+        // ===== Fehler pro Semester =====
+        for (int sem = 0; sem < semesterCount; sem++)
+        {
+            int errors = students.Count(st =>
+                st.Result != null &&
+                st.Result.Count > sem &&
+                st.Result[sem] == "Fehler");
+
+            sb.AppendLine($"Semester {sem + 1}: {errors} Fehler");
+        }
+
         return sb.ToString();
     }
 }