feat: Kategorien-Verwaltung auf der Admin-Seite

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

finance/app/routers/categories.py

@@ -48,6 +48,22 @@ def create_category(data: CategoryIn, session: Session = Depends(get_session)):
     return CategoryOut.model_validate(cat)
 
 
+@router.patch("/categories/{category_id}", response_model=CategoryOut)
+def patch_category(category_id: int, data: CategoryIn,
+                   session: Session = Depends(get_session)):
+    cat = session.get(Category, category_id)
+    if cat is None:
+        raise HTTPException(404, "Kategorie nicht gefunden")
+    clash = session.execute(
+        select(Category).where(Category.name == data.name)).scalar()
+    if clash is not None and clash.id != category_id:
+        raise HTTPException(409, "Kategorie existiert bereits")
+    cat.name = data.name
+    session.commit()
+    session.refresh(cat)
+    return CategoryOut.model_validate(cat)
+
+
 @router.get("/category-rules", response_model=list[CategoryRuleOut])
 def list_category_rules(session: Session = Depends(get_session)):
     rules = session.execute(