feat: Reduce minimum audit log deletion period to 6 days and update enrollment last access only for active enrollments.

Backend/src/controllers/AuditController.ts

@@ -169,8 +169,8 @@ export class AuditController {
             throw new ValidationError('No token provided');
         }
 
-        if (days < 30) {
-            throw new ValidationError('Cannot delete logs newer than 30 days');
+        if (days < 6) {
+            throw new ValidationError('Cannot delete logs newer than 6 days');
         }
 
         const deleted = await auditService.deleteOldLogs(days);

Backend/src/services/CoursesStudent.service.ts

@@ -341,15 +341,17 @@ export class CoursesStudentService {
             }
 
             // Update last_accessed_at (fire-and-forget — ไม่ block response)
-            prisma.enrollment.update({
-                where: {
-                    unique_enrollment: {
-                        user_id: decoded.id,
-                        course_id,
+            if (enrollment.status === 'ENROLLED') {
+                prisma.enrollment.update({
+                    where: {
+                        unique_enrollment: {
+                            user_id: decoded.id,
+                            course_id,
+                        },
                     },
-                },
-                data: { last_accessed_at: new Date() },
-            }).catch(err => logger.warn(`Failed to update last_accessed_at: ${err}`));
+                    data: { last_accessed_at: new Date() },
+                }).catch(err => logger.warn(`Failed to update last_accessed_at: ${err}`));
+            }
 
             // Get all lesson progress for this user and course
             const lessonIds = course.chapters.flatMap(ch => ch.lessons.map(l => l.id));