refactor: localize UI labels and store filenames

src/ccma/ui/labels.py

@@ -0,0 +1,26 @@
+from __future__ import annotations
+
+from collections.abc import Mapping
+
+THEME_LABELS = {
+    "dark": "Dunkel",
+    "light": "Hell",
+}
+
+CLAIM_ITEM_TYPE_LABELS = {
+    "base": "Grundposition",
+    "product": "Produkt",
+    "service": "Dienstleistung",
+    "fee": "Gebühr",
+    "discount": "Rabatt",
+    "credit": "Gutschrift",
+    "correction": "Korrektur",
+}
+
+
+def display_label(labels: Mapping[str, str], key: str) -> str:
+    return labels.get(key, key)
+
+
+def storage_key(labels: Mapping[str, str], label: str) -> str:
+    return next((key for key, value in labels.items() if value == label), label)