feat: Bearbeitungssperren und Versionskonfliktschutz ergänzen

netbox_documentation/models.py

@@ -169,3 +169,17 @@ class ExcelImportPreview(models.Model):
 
     def __str__(self):
         return self.original_name
+
+
+class DocumentEditLock(models.Model):
+    """Short-lived advisory lock; optimistic version checks remain authoritative."""
+    _netbox_private = True
+
+    document = models.OneToOneField(Document, on_delete=models.SET_NULL, null=True, related_name="edit_lock")
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True)
+    token = models.UUIDField(default=uuid.uuid4, editable=False)
+    acquired = models.DateTimeField(auto_now_add=True)
+    heartbeat = models.DateTimeField(auto_now=True)
+
+    def __str__(self):
+        return f"{self.document} – {self.user}"