fix: Import ersetzt bestehende Fragen der betroffenen Fächer

app/Http/Controllers/Admin/QuestionController.php

@@ -129,9 +129,21 @@ class QuestionController extends Controller {
             return back()->with('error', 'Ungültiges JSON-Format.');
         }
         $subjects = Subject::pluck('id','slug');
+
+        // Collect subject IDs that appear in the file
+        $affectedIds = collect($raw)
+            ->pluck('subject')
+            ->unique()
+            ->filter(fn($s) => isset($subjects[$s]))
+            ->map(fn($s) => $subjects[$s])
+            ->values();
+
         $imported = 0;
         $skipped  = 0;
-        DB::transaction(function() use ($raw, $subjects, &$imported, &$skipped) {
+        DB::transaction(function() use ($raw, $subjects, $affectedIds, &$imported, &$skipped) {
+            // Delete existing questions for those subjects
+            Question::whereIn('subject_id', $affectedIds)->delete();
+
             foreach ($raw as $item) {
                 if (empty($item['subject']) || !isset($subjects[$item['subject']])) { $skipped++; continue; }
                 if (empty($item['question_text']))                                  { $skipped++; continue; }
@@ -154,7 +166,7 @@ class QuestionController extends Controller {
                 $imported++;
             }
         });
-        $msg = "{$imported} Fragen importiert.";
+        $msg = "{$imported} Fragen importiert (bestehende Fragen der betroffenen Fächer wurden ersetzt).";
         if ($skipped) $msg .= " {$skipped} übersprungen (unbekanntes Fach oder fehlender Text).";
         return back()->with('success', $msg);
     }