feat: integer cents money handling, order page fixes, and vendor filter persistence

Money Handling Architecture:
- Store all monetary values as integer cents (€105.91 = 10591)
- Add app/utils/money.py with Money class and conversion helpers
- Add static/shared/js/money.js for frontend formatting
- Update all database models to use _cents columns (Product, Order, etc.)
- Update CSV processor to convert prices to cents on import
- Add Alembic migration for Float to Integer conversion
- Create .architecture-rules/money.yaml with 7 validation rules
- Add docs/architecture/money-handling.md documentation

Order Details Page Fixes:
- Fix customer name showing 'undefined undefined' - use flat field names
- Fix vendor info empty - add vendor_name/vendor_code to OrderDetailResponse
- Fix shipping address using wrong nested object structure
- Enrich order detail API response with vendor info

Vendor Filter Persistence Fixes:
- Fix orders.js: restoreSavedVendor now sets selectedVendor and filters
- Fix orders.js: init() only loads orders if no saved vendor to restore
- Fix marketplace-letzshop.js: restoreSavedVendor calls selectVendor()
- Fix marketplace-letzshop.js: clearVendorSelection clears TomSelect dropdown
- Align vendor selector placeholder text between pages

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

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

models/database/order.py

@@ -11,13 +11,15 @@ Design principles:
 - customer_id FK links to Customer record (may be inactive for marketplace imports)
 - channel field distinguishes order source
 - external_* fields store marketplace-specific references
+
+Money values are stored as integer cents (e.g., €105.91 = 10591).
+See docs/architecture/money-handling.md for details.
 """
 
 from sqlalchemy import (
     Boolean,
     Column,
     DateTime,
-    Float,
     ForeignKey,
     Index,
     Integer,
@@ -32,6 +34,7 @@ from sqlalchemy.dialects.sqlite import JSON
 from sqlalchemy.orm import relationship
 
 from app.core.database import Base
+from app.utils.money import cents_to_euros, euros_to_cents
 from models.database.base import TimestampMixin
 
 
@@ -41,6 +44,8 @@ class Order(Base, TimestampMixin):
 
     Stores orders from direct sales and marketplaces (Letzshop, etc.)
     with snapshotted customer and address data.
+
+    All monetary amounts are stored as integer cents for precision.
     """
 
     __tablename__ = "orders"
@@ -76,12 +81,12 @@ class Order(Base, TimestampMixin):
     # refunded: order refunded
     status = Column(String(50), nullable=False, default="pending", index=True)
 
-    # === Financials ===
-    subtotal = Column(Float, nullable=True)  # May not be available from marketplace
-    tax_amount = Column(Float, nullable=True)
-    shipping_amount = Column(Float, nullable=True)
-    discount_amount = Column(Float, nullable=True)
-    total_amount = Column(Float, nullable=False)
+    # === Financials (stored as integer cents) ===
+    subtotal_cents = Column(Integer, nullable=True)  # May not be available from marketplace
+    tax_amount_cents = Column(Integer, nullable=True)
+    shipping_amount_cents = Column(Integer, nullable=True)
+    discount_amount_cents = Column(Integer, nullable=True)
+    total_amount_cents = Column(Integer, nullable=False)
     currency = Column(String(10), default="EUR")
 
     # === Customer Snapshot (preserved at order time) ===
@@ -115,6 +120,9 @@ class Order(Base, TimestampMixin):
     shipping_method = Column(String(100), nullable=True)
     tracking_number = Column(String(100), nullable=True)
     tracking_provider = Column(String(100), nullable=True)
+    tracking_url = Column(String(500), nullable=True)  # Full tracking URL
+    shipment_number = Column(String(100), nullable=True)  # Carrier shipment number (e.g., H74683403433)
+    shipping_carrier = Column(String(50), nullable=True)  # Carrier code (greco, colissimo, etc.)
 
     # === Notes ===
     customer_notes = Column(Text, nullable=True)
@@ -146,6 +154,68 @@ class Order(Base, TimestampMixin):
     def __repr__(self):
         return f"<Order(id={self.id}, order_number='{self.order_number}', channel='{self.channel}', status='{self.status}')>"
 
+    # === PRICE PROPERTIES (Euro convenience accessors) ===
+
+    @property
+    def subtotal(self) -> float | None:
+        """Get subtotal in euros."""
+        if self.subtotal_cents is not None:
+            return cents_to_euros(self.subtotal_cents)
+        return None
+
+    @subtotal.setter
+    def subtotal(self, value: float | None):
+        """Set subtotal from euros."""
+        self.subtotal_cents = euros_to_cents(value) if value is not None else None
+
+    @property
+    def tax_amount(self) -> float | None:
+        """Get tax amount in euros."""
+        if self.tax_amount_cents is not None:
+            return cents_to_euros(self.tax_amount_cents)
+        return None
+
+    @tax_amount.setter
+    def tax_amount(self, value: float | None):
+        """Set tax amount from euros."""
+        self.tax_amount_cents = euros_to_cents(value) if value is not None else None
+
+    @property
+    def shipping_amount(self) -> float | None:
+        """Get shipping amount in euros."""
+        if self.shipping_amount_cents is not None:
+            return cents_to_euros(self.shipping_amount_cents)
+        return None
+
+    @shipping_amount.setter
+    def shipping_amount(self, value: float | None):
+        """Set shipping amount from euros."""
+        self.shipping_amount_cents = euros_to_cents(value) if value is not None else None
+
+    @property
+    def discount_amount(self) -> float | None:
+        """Get discount amount in euros."""
+        if self.discount_amount_cents is not None:
+            return cents_to_euros(self.discount_amount_cents)
+        return None
+
+    @discount_amount.setter
+    def discount_amount(self, value: float | None):
+        """Set discount amount from euros."""
+        self.discount_amount_cents = euros_to_cents(value) if value is not None else None
+
+    @property
+    def total_amount(self) -> float:
+        """Get total amount in euros."""
+        return cents_to_euros(self.total_amount_cents)
+
+    @total_amount.setter
+    def total_amount(self, value: float):
+        """Set total amount from euros."""
+        self.total_amount_cents = euros_to_cents(value)
+
+    # === NAME PROPERTIES ===
+
     @property
     def customer_full_name(self) -> str:
         """Customer full name from snapshot."""
@@ -173,6 +243,8 @@ class OrderItem(Base, TimestampMixin):
 
     Stores product snapshot at time of order plus external references
     for marketplace items.
+
+    All monetary amounts are stored as integer cents for precision.
     """
 
     __tablename__ = "order_items"
@@ -187,10 +259,10 @@ class OrderItem(Base, TimestampMixin):
     gtin = Column(String(50), nullable=True)  # EAN/UPC/ISBN etc.
     gtin_type = Column(String(20), nullable=True)  # ean13, upc, isbn, etc.
 
-    # === Pricing ===
+    # === Pricing (stored as integer cents) ===
     quantity = Column(Integer, nullable=False)
-    unit_price = Column(Float, nullable=False)
-    total_price = Column(Float, nullable=False)
+    unit_price_cents = Column(Integer, nullable=False)
+    total_price_cents = Column(Integer, nullable=False)
 
     # === External References (for marketplace items) ===
     external_item_id = Column(String(100), nullable=True)  # e.g., Letzshop inventory unit ID
@@ -222,6 +294,30 @@ class OrderItem(Base, TimestampMixin):
     def __repr__(self):
         return f"<OrderItem(id={self.id}, order_id={self.order_id}, product_id={self.product_id}, gtin='{self.gtin}')>"
 
+    # === PRICE PROPERTIES (Euro convenience accessors) ===
+
+    @property
+    def unit_price(self) -> float:
+        """Get unit price in euros."""
+        return cents_to_euros(self.unit_price_cents)
+
+    @unit_price.setter
+    def unit_price(self, value: float):
+        """Set unit price from euros."""
+        self.unit_price_cents = euros_to_cents(value)
+
+    @property
+    def total_price(self) -> float:
+        """Get total price in euros."""
+        return cents_to_euros(self.total_price_cents)
+
+    @total_price.setter
+    def total_price(self, value: float):
+        """Set total price from euros."""
+        self.total_price_cents = euros_to_cents(value)
+
+    # === STATUS PROPERTIES ===
+
     @property
     def is_confirmed(self) -> bool:
         """Check if item has been confirmed (available or unavailable)."""