feat: update Pydantic schemas for unified order model

- Add AddressSnapshot and CustomerSnapshot schemas
- Update OrderItemResponse with gtin fields and item_state
- Update OrderResponse with all snapshot fields
- Add OrderListItem for simplified list views
- Add Letzshop-specific schemas (LetzshopOrderImport, LetzshopShippingInfo)
- Update AdminOrderItem with new fields

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

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

models/schema/letzshop.py

@@ -91,6 +91,9 @@ class LetzshopOrderBase(BaseModel):
     letzshop_state: str | None = None
     customer_email: str | None = None
     customer_name: str | None = None
+    customer_locale: str | None = None
+    shipping_country_iso: str | None = None
+    billing_country_iso: str | None = None
     total_amount: str | None = None
     currency: str = "EUR"
 
@@ -120,6 +123,7 @@ class LetzshopOrderResponse(LetzshopOrderBase):
     tracking_number: str | None
     tracking_carrier: str | None
     inventory_units: list[dict[str, Any]] | None
+    order_date: datetime | None
     created_at: datetime
     updated_at: datetime
 
@@ -368,3 +372,55 @@ class LetzshopJobsListResponse(BaseModel):
 
     jobs: list[LetzshopJobItem]
     total: int
+
+
+# ============================================================================
+# Historical Import Job Schemas
+# ============================================================================
+
+
+class LetzshopHistoricalImportJobResponse(BaseModel):
+    """Schema for historical import job status (polling endpoint)."""
+
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    vendor_id: int
+    status: str  # pending, fetching, processing, completed, failed
+    current_phase: str | None = None  # "confirmed" or "declined"
+
+    # Fetch progress
+    current_page: int = 0
+    total_pages: int | None = None
+    shipments_fetched: int = 0
+
+    # Processing progress
+    orders_processed: int = 0
+    orders_imported: int = 0
+    orders_updated: int = 0
+    orders_skipped: int = 0
+
+    # EAN matching stats
+    products_matched: int = 0
+    products_not_found: int = 0
+
+    # Phase-specific stats (when complete)
+    confirmed_stats: dict[str, Any] | None = None
+    declined_stats: dict[str, Any] | None = None
+
+    # Error handling
+    error_message: str | None = None
+
+    # Timing
+    started_at: datetime | None = None
+    completed_at: datetime | None = None
+    created_at: datetime
+    updated_at: datetime
+
+
+class LetzshopHistoricalImportStartResponse(BaseModel):
+    """Schema for starting a historical import job."""
+
+    job_id: int
+    status: str = "pending"
+    message: str = "Historical import job started"