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/schema/order.py

@@ -270,6 +270,9 @@ class OrderResponse(BaseModel):
     shipping_method: str | None
     tracking_number: str | None
     tracking_provider: str | None
+    tracking_url: str | None = None
+    shipment_number: str | None = None
+    shipping_carrier: str | None = None
 
     # Notes
     customer_notes: str | None
@@ -302,6 +305,10 @@ class OrderDetailResponse(OrderResponse):
 
     items: list[OrderItemResponse] = []
 
+    # Vendor info (enriched by API)
+    vendor_name: str | None = None
+    vendor_code: str | None = None
+
 
 class OrderListResponse(BaseModel):
     """Schema for paginated order list."""
@@ -345,6 +352,9 @@ class OrderListItem(BaseModel):
     # Tracking
     tracking_number: str | None
     tracking_provider: str | None
+    tracking_url: str | None = None
+    shipment_number: str | None = None
+    shipping_carrier: str | None = None
 
     # Item count
     item_count: int = 0
@@ -394,6 +404,9 @@ class AdminOrderItem(BaseModel):
     ship_country_iso: str
     tracking_number: str | None
     tracking_provider: str | None
+    tracking_url: str | None = None
+    shipment_number: str | None = None
+    shipping_carrier: str | None = None
 
     # Item count
     item_count: int = 0
@@ -534,3 +547,26 @@ class LetzshopOrderConfirmRequest(BaseModel):
     """Schema for confirming/declining order items."""
 
     items: list[LetzshopOrderConfirmItem]
+
+
+# ============================================================================
+# Mark as Shipped Schemas
+# ============================================================================
+
+
+class MarkAsShippedRequest(BaseModel):
+    """Schema for marking an order as shipped with tracking info."""
+
+    tracking_number: str | None = Field(None, max_length=100)
+    tracking_url: str | None = Field(None, max_length=500)
+    shipping_carrier: str | None = Field(None, max_length=50)
+
+
+class ShippingLabelInfo(BaseModel):
+    """Shipping label information for an order."""
+
+    shipment_number: str | None = None
+    shipping_carrier: str | None = None
+    label_url: str | None = None
+    tracking_number: str | None = None
+    tracking_url: str | None = None