feat: verbessere SRS-Logik zur Bestimmung des nächsten Fälligkeitsdatums für neu erstellte Elemente und erweitere die API-Anfragen für kursweite fällige Items

backend/services/vocabService.js

@@ -191,6 +191,17 @@ export default class VocabService {
       if (existingByKey.has(entry.itemKey)) {
         continue;
       }
+
+      // Determine safe default nextDueAt for newly created items:
+      // - default: next calendar day at 08:00
+      // - ensure at least 24 hours after creation
+      const createdAt = new Date(now);
+      const nextCalendar08 = new Date(createdAt);
+      nextCalendar08.setHours(8, 0, 0, 0);
+      nextCalendar08.setDate(nextCalendar08.getDate() + 1);
+      const min24h = new Date(createdAt.getTime() + 24 * 60 * 60 * 1000);
+      const safeNextDue = nextCalendar08.getTime() < min24h.getTime() ? min24h : nextCalendar08;
+
       const created = await VocabSrsItem.create({
         userId,
         courseId: Number(courseId),
@@ -199,7 +210,7 @@ export default class VocabService {
         learning: entry.learning,
         reference: entry.reference,
         direction: entry.direction,
-        nextDueAt: now
+        nextDueAt: safeNextDue
       });
       createdItems.push(created);
       existingByKey.set(entry.itemKey, created);