Minor version bump (1.x.0) is appropriate because:

✅ New functionality added (soft delete system)
✅ Backward compatible (existing features unchanged)
✅ Significant enhancement (complete temporal tracking system)
✅ API additions (new endpoints, parameters)
✅ UI enhancements (new components, visual indicators)

backend/schemas.py

@@ -1,6 +1,6 @@
 from pydantic import BaseModel, Field
 from typing import Optional, List
-from datetime import datetime
+from datetime import datetime, date
 
 # Brand schemas
 class BrandBase(BaseModel):
@@ -70,7 +70,7 @@ class ProductBase(BaseModel):
     weight_unit: str = "g"
 
 class ProductCreate(ProductBase):
-    pass
+    valid_from: Optional[date] = None  # If not provided, will use current date
 
 class ProductUpdate(BaseModel):
     name: Optional[str] = None
@@ -79,6 +79,7 @@ class ProductUpdate(BaseModel):
     organic: Optional[bool] = None
     weight: Optional[float] = None
     weight_unit: Optional[str] = None
+    valid_from: Optional[date] = None  # If not provided, will use current date
 
 class Product(ProductBase):
     id: int
@@ -90,6 +91,54 @@ class Product(ProductBase):
     class Config:
         from_attributes = True
 
+# Historical Product schemas
+class ProductHistory(BaseModel):
+    history_id: int
+    id: int  # Original product ID
+    name: str
+    category_id: int
+    brand_id: Optional[int] = None
+    organic: bool = False
+    weight: Optional[float] = None
+    weight_unit: str = "g"
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+    valid_from: date
+    valid_to: date
+    deleted: bool
+    operation: str  # 'U' for Update, 'D' for Delete
+    archived_at: datetime
+    
+    class Config:
+        from_attributes = True
+
+class ProductAtDate(BaseModel):
+    id: int
+    name: str
+    category_id: int
+    category: GroceryCategory
+    brand_id: Optional[int] = None
+    brand: Optional[Brand] = None
+    organic: bool = False
+    weight: Optional[float] = None
+    weight_unit: str = "g"
+    valid_from: date
+    valid_to: date
+    deleted: bool
+    was_current: bool  # True if from current table, False if from history
+    
+    class Config:
+        from_attributes = True
+
+class ProductAtPurchase(BaseModel):
+    product: ProductAtDate
+    amount: float
+    price: float
+    discount: bool
+    
+    class Config:
+        from_attributes = True
+
 # Shop schemas
 class ShopBase(BaseModel):
     name: str