refactor: migrate modules from re-exports to canonical implementations

Move actual code implementations into module directories:
- orders: 5 services, 4 models, order/invoice schemas
- inventory: 3 services, 2 models, 30+ schemas
- customers: 3 services, 2 models, customer schemas
- messaging: 3 services, 2 models, message/notification schemas
- monitoring: background_tasks_service
- marketplace: 5+ services including letzshop submodule
- dev_tools: code_quality_service, test_runner_service
- billing: billing_service
- contracts: definition.py

Legacy files in app/services/, models/database/, models/schema/
now re-export from canonical module locations for backwards
compatibility. Architecture validator passes with 0 errors.

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

app/modules/inventory/schemas/__init__.py

@@ -2,27 +2,77 @@
 """
 Inventory module Pydantic schemas.
 
-Re-exports inventory-related schemas from their source locations.
+This module contains the canonical implementations of inventory-related schemas.
 """
 
-from models.schema.inventory import (
+from app.modules.inventory.schemas.inventory import (
+    # Base schemas
+    InventoryBase,
     InventoryCreate,
     InventoryAdjust,
+    InventoryUpdate,
     InventoryReserve,
+    # Response schemas
     InventoryResponse,
+    InventoryLocationResponse,
+    ProductInventorySummary,
     InventoryListResponse,
-    InventoryTransactionResponse,
+    InventoryMessageResponse,
+    InventorySummaryResponse,
+    # Admin schemas
+    AdminInventoryCreate,
+    AdminInventoryAdjust,
     AdminInventoryItem,
+    AdminInventoryListResponse,
+    AdminInventoryStats,
     AdminLowStockItem,
+    AdminVendorWithInventory,
+    AdminVendorsWithInventoryResponse,
+    AdminInventoryLocationsResponse,
+    # Transaction schemas
+    InventoryTransactionResponse,
+    InventoryTransactionWithProduct,
+    InventoryTransactionListResponse,
+    ProductTransactionHistoryResponse,
+    OrderTransactionHistoryResponse,
+    # Admin transaction schemas
+    AdminInventoryTransactionItem,
+    AdminInventoryTransactionListResponse,
+    AdminTransactionStatsResponse,
 )
 
 __all__ = [
+    # Base schemas
+    "InventoryBase",
     "InventoryCreate",
     "InventoryAdjust",
+    "InventoryUpdate",
     "InventoryReserve",
+    # Response schemas
     "InventoryResponse",
+    "InventoryLocationResponse",
+    "ProductInventorySummary",
     "InventoryListResponse",
-    "InventoryTransactionResponse",
+    "InventoryMessageResponse",
+    "InventorySummaryResponse",
+    # Admin schemas
+    "AdminInventoryCreate",
+    "AdminInventoryAdjust",
     "AdminInventoryItem",
+    "AdminInventoryListResponse",
+    "AdminInventoryStats",
     "AdminLowStockItem",
+    "AdminVendorWithInventory",
+    "AdminVendorsWithInventoryResponse",
+    "AdminInventoryLocationsResponse",
+    # Transaction schemas
+    "InventoryTransactionResponse",
+    "InventoryTransactionWithProduct",
+    "InventoryTransactionListResponse",
+    "ProductTransactionHistoryResponse",
+    "OrderTransactionHistoryResponse",
+    # Admin transaction schemas
+    "AdminInventoryTransactionItem",
+    "AdminInventoryTransactionListResponse",
+    "AdminTransactionStatsResponse",
 ]