snapshot: modularize workflow model layer by responsibility

backend/workflows/model_shared.py

@@ -0,0 +1,14 @@
+from django.utils.translation import gettext_lazy as _
+
+
+def normalized_language_code(value: str | None) -> str:
+    lang = (value or '').strip().split('-')[0].lower()
+    return lang or 'de'
+
+
+REQUEST_STATUS_CHOICES = [
+    ('submitted', _('Eingereicht')),
+    ('processing', _('In Bearbeitung')),
+    ('completed', _('Abgeschlossen')),
+    ('failed', _('Fehlgeschlagen')),
+]