fix: repair Rentman equipment sync with real API field mapping

- Map real Rentman fields: price -> rental_price, folder -> category/subcategory
  (resolved via folder hierarchy to top-level categories), code -> number,
  shop_description_long (fallback short/external_remark) -> description (HTML stripped)
- Sync only in_shop items; exclude archived/temporary from public catalog
- Extract known brands from equipment names (d&b, Shure, Pioneer, ...)
- Build specifications from physical fields (power, weight, dimensions)
- Persist equipment images in docker volume (survive redeploys)
- Router: filter available items, add price_asc/price_desc sorting
- Frontend: show prices in catalog card, detail page and cart with
  per-day subtotal; price sorting options
- Tests: use real Rentman field names in fixtures, mock folder_map

backend/app/routers/equipment.py

@@ -30,8 +30,8 @@ async def list_equipment(
     if cached:
         return cached
 
-    query = select(EquipmentCache)
-    count_query = select(func.count(EquipmentCache.id))
+    query = select(EquipmentCache).where(EquipmentCache.available == True)  # noqa: E712
+    count_query = select(func.count(EquipmentCache.id)).where(EquipmentCache.available == True)  # noqa: E712
 
     if search:
         query = query.where(EquipmentCache.name.ilike(f"%{search}%"))
@@ -42,6 +42,10 @@ async def list_equipment(
 
     if sort == "name_desc":
         query = query.order_by(EquipmentCache.name.desc())
+    elif sort == "price_asc":
+        query = query.order_by(EquipmentCache.rental_price.asc().nulls_last(), EquipmentCache.name.asc())
+    elif sort == "price_desc":
+        query = query.order_by(EquipmentCache.rental_price.desc().nulls_last(), EquipmentCache.name.asc())
     else:
         query = query.order_by(EquipmentCache.name.asc())
 
@@ -70,7 +74,9 @@ async def list_categories(db: AsyncSession = Depends(get_db)) -> Any:
     if cached:
         return cached
     result = await db.execute(
-        select(EquipmentCache.category).distinct().where(EquipmentCache.category.isnot(None))
+        select(EquipmentCache.category).distinct().where(
+            EquipmentCache.category.isnot(None), EquipmentCache.available == True  # noqa: E712
+        )
     )
     categories = [row[0] for row in result.fetchall() if row[0]]
     await cache.set("equipment:categories", categories, ttl=3600)