feat: add VAT tax rate, cost, and Letzshop feed settings

Product Model:
- Add tax_rate_percent (NOT NULL, default 17) for Luxembourg VAT
- Add cost_cents for profit calculation
- Add profit calculation properties: net_price, vat_amount, profit, margin
- Rename supplier_cost_cents to cost_cents

MarketplaceProduct Model:
- Add tax_rate_percent (NOT NULL, default 17)

Vendor Model (Letzshop feed settings):
- letzshop_default_tax_rate: Default VAT for new products (0, 3, 8, 14, 17)
- letzshop_boost_sort: Product sort priority (0.0-10.0)
- letzshop_delivery_method: nationwide, package_delivery, self_collect
- letzshop_preorder_days: Pre-order shipping delay

VAT Strategy:
- Store prices as gross (VAT-inclusive) for B2C
- Calculate net from gross when needed for profit
- Luxembourg VAT rates: 0%, 3%, 8%, 14%, 17%

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

models/database/marketplace_product.py

@@ -100,6 +100,11 @@ class MarketplaceProduct(Base, TimestampMixin):
     sale_price_cents = Column(Integer)  # Parsed numeric sale price in cents
     currency = Column(String(3), default="EUR")
 
+    # === TAX / VAT ===
+    # Luxembourg VAT rates: 0 (exempt), 3 (super-reduced), 8 (reduced), 14 (intermediate), 17 (standard)
+    # Prices are stored as gross (VAT-inclusive). Default to standard rate.
+    tax_rate_percent = Column(Integer, default=17, nullable=False)
+
     # === MEDIA ===
     image_link = Column(String)
     additional_image_link = Column(String)  # Legacy single string

models/database/product.py

@@ -75,10 +75,15 @@ class Product(Base, TimestampMixin):
     download_url = Column(String)
     license_type = Column(String(50))
 
-    # === SUPPLIER TRACKING ===
+    # === TAX / VAT ===
+    # Luxembourg VAT rates: 0 (exempt), 3 (super-reduced), 8 (reduced), 14 (intermediate), 17 (standard)
+    # Prices are stored as gross (VAT-inclusive). Tax rate is used for profit calculation.
+    tax_rate_percent = Column(Integer, default=17, nullable=False)
+
+    # === SUPPLIER TRACKING & COST ===
     supplier = Column(String(50))  # 'codeswholesale', 'internal', etc.
     supplier_product_id = Column(String)  # Supplier's product reference
-    supplier_cost_cents = Column(Integer)  # What we pay the supplier (in cents)
+    cost_cents = Column(Integer)  # What vendor pays to acquire (in cents) - for profit calculation
     margin_percent_x100 = Column(Integer)  # Markup percentage * 100 (e.g., 25.5% = 2550)
 
     # === VENDOR-SPECIFIC (No inheritance) ===
@@ -165,16 +170,16 @@ class Product(Base, TimestampMixin):
         self.sale_price_cents = euros_to_cents(value) if value is not None else None
 
     @property
-    def supplier_cost(self) -> float | None:
-        """Get supplier cost in euros."""
-        if self.supplier_cost_cents is not None:
-            return cents_to_euros(self.supplier_cost_cents)
+    def cost(self) -> float | None:
+        """Get cost in euros (what vendor pays to acquire)."""
+        if self.cost_cents is not None:
+            return cents_to_euros(self.cost_cents)
         return None
 
-    @supplier_cost.setter
-    def supplier_cost(self, value: float | None):
-        """Set supplier cost from euros."""
-        self.supplier_cost_cents = euros_to_cents(value) if value is not None else None
+    @cost.setter
+    def cost(self, value: float | None):
+        """Set cost from euros."""
+        self.cost_cents = euros_to_cents(value) if value is not None else None
 
     @property
     def margin_percent(self) -> float | None:
@@ -188,6 +193,77 @@ class Product(Base, TimestampMixin):
         """Set margin percent."""
         self.margin_percent_x100 = int(value * 100) if value is not None else None
 
+    # === TAX / PROFIT CALCULATION PROPERTIES ===
+
+    @property
+    def net_price_cents(self) -> int | None:
+        """Calculate net price (excluding VAT) from gross price.
+
+        Formula: Net = Gross / (1 + rate/100)
+        Example: €119 gross at 17% VAT = €119 / 1.17 = €101.71 net
+        """
+        gross = self.effective_price_cents
+        if gross is None:
+            return None
+        # Use integer math to avoid floating point issues
+        # Net = Gross * 100 / (100 + rate)
+        return int(gross * 100 / (100 + self.tax_rate_percent))
+
+    @property
+    def net_price(self) -> float | None:
+        """Get net price in euros."""
+        cents = self.net_price_cents
+        return cents_to_euros(cents) if cents is not None else None
+
+    @property
+    def vat_amount_cents(self) -> int | None:
+        """Calculate VAT amount in cents.
+
+        Formula: VAT = Gross - Net
+        """
+        gross = self.effective_price_cents
+        net = self.net_price_cents
+        if gross is None or net is None:
+            return None
+        return gross - net
+
+    @property
+    def vat_amount(self) -> float | None:
+        """Get VAT amount in euros."""
+        cents = self.vat_amount_cents
+        return cents_to_euros(cents) if cents is not None else None
+
+    @property
+    def profit_cents(self) -> int | None:
+        """Calculate profit in cents.
+
+        Formula: Profit = Net Revenue - Cost
+        Returns None if cost is not set.
+        """
+        net = self.net_price_cents
+        if net is None or self.cost_cents is None:
+            return None
+        return net - self.cost_cents
+
+    @property
+    def profit(self) -> float | None:
+        """Get profit in euros."""
+        cents = self.profit_cents
+        return cents_to_euros(cents) if cents is not None else None
+
+    @property
+    def profit_margin_percent(self) -> float | None:
+        """Calculate profit margin as percentage of net revenue.
+
+        Formula: Margin% = (Profit / Net) * 100
+        Example: €41.71 profit on €101.71 net = 41.0% margin
+        """
+        net = self.net_price_cents
+        profit = self.profit_cents
+        if net is None or profit is None or net == 0:
+            return None
+        return round((profit / net) * 100, 2)
+
     # === EFFECTIVE PROPERTIES (Override Pattern) ===
 
     @property

models/database/vendor.py

@@ -57,6 +57,26 @@ class Vendor(Base, TimestampMixin):
     letzshop_csv_url_en = Column(String)  # URL for English CSV in Letzshop
     letzshop_csv_url_de = Column(String)  # URL for German CSV in Letzshop
 
+    # ========================================================================
+    # Letzshop Feed Settings (atalanda namespace)
+    # ========================================================================
+    # These are default values applied to all products in the Letzshop feed
+    # See https://letzshop.lu/en/dev#google_csv for documentation
+
+    # Default VAT rate for new products: 0 (exempt), 3 (super-reduced), 8 (reduced), 14 (intermediate), 17 (standard)
+    letzshop_default_tax_rate = Column(Integer, default=17, nullable=False)
+
+    # Product sort priority on Letzshop (0.0-10.0, higher = displayed first)
+    # Note: Having all products rated above 7 is not permitted by Letzshop
+    letzshop_boost_sort = Column(String(10), default="5.0")  # Stored as string for precision
+
+    # Delivery method: 'nationwide', 'package_delivery', 'self_collect' (comma-separated for multiple)
+    # 'nationwide' automatically includes package_delivery and self_collect
+    letzshop_delivery_method = Column(String(100), default="package_delivery")
+
+    # Pre-order days: number of days before item ships (default 1 day)
+    letzshop_preorder_days = Column(Integer, default=1)
+
     # Status (vendor-specific, can differ from company status)
     is_active = Column(
         Boolean, default=True