Refactor transport calculation into shared domain

roll_calculation.py

@@ -301,6 +301,28 @@ class ArticleRepository:
         }
 
 
+def get_article(
+    article_number: str | None = None,
+    article_name_hint: str | None = None,
+    *,
+    article_repository: ArticleRepository | None = None,
+) -> dict[str, Any]:
+    """Resolve one article through the canonical article repository."""
+    for field, value in (
+        ("article_number", article_number),
+        ("article_name_hint", article_name_hint),
+    ):
+        if value is not None and not isinstance(value, str):
+            return {
+                "status": "invalid_parameter",
+                "invalid": [{"field": field, "message": f"{field} must be text"}],
+            }
+    article_number = article_number.strip() if article_number else None
+    article_name_hint = article_name_hint.strip() if article_name_hint else None
+    repository = article_repository or ArticleRepository.load()
+    return repository.resolve(article_number, article_name_hint)
+
+
 def _canonical_name(value: str) -> str:
     value = value.casefold().replace("×", " x ")
     tokens = re.findall(r"\d+(?:[.,]\d+)?|[^\W\d_]+", value)