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>

models/schema/notification.py

@@ -1,152 +1,53 @@
 # models/schema/notification.py
 """
-Notification Pydantic schemas for API validation and responses.
+LEGACY LOCATION - Re-exports from module for backwards compatibility.
 
-This module provides schemas for:
-- Vendor notifications (list, read, delete)
-- Notification settings management
-- Notification email templates
-- Unread counts and statistics
+The canonical implementation is now in:
+    app/modules/messaging/schemas/notification.py
+
+This file exists to maintain backwards compatibility with code that
+imports from the old location. All new code should import directly
+from the module:
+
+    from app.modules.messaging.schemas import notification
 """
 
-from datetime import datetime
-from typing import Any
+from app.modules.messaging.schemas.notification import (
+    # Response schemas
+    MessageResponse,
+    UnreadCountResponse,
+    # Notification schemas
+    NotificationResponse,
+    NotificationListResponse,
+    # Settings schemas
+    NotificationSettingsResponse,
+    NotificationSettingsUpdate,
+    # Template schemas
+    NotificationTemplateResponse,
+    NotificationTemplateListResponse,
+    NotificationTemplateUpdate,
+    # Test notification
+    TestNotificationRequest,
+    # Alert statistics
+    AlertStatisticsResponse,
+)
 
-from pydantic import BaseModel, Field
-
-# ============================================================================
-# SHARED RESPONSE SCHEMAS
-# ============================================================================
-
-
-class MessageResponse(BaseModel):
-    """Generic message response for simple operations."""
-
-    message: str
-
-
-class UnreadCountResponse(BaseModel):
-    """Response for unread notification count."""
-
-    unread_count: int
-    message: str | None = None
-
-
-# ============================================================================
-# NOTIFICATION SCHEMAS
-# ============================================================================
-
-
-class NotificationResponse(BaseModel):
-    """Single notification response."""
-
-    id: int
-    type: str
-    title: str
-    message: str
-    is_read: bool
-    read_at: datetime | None = None
-    priority: str = "normal"
-    action_url: str | None = None
-    metadata: dict[str, Any] | None = None
-    created_at: datetime
-
-    model_config = {"from_attributes": True}
-
-
-class NotificationListResponse(BaseModel):
-    """Paginated list of notifications."""
-
-    notifications: list[NotificationResponse] = []
-    total: int = 0
-    unread_count: int = 0
-    message: str | None = None
-
-
-# ============================================================================
-# NOTIFICATION SETTINGS SCHEMAS
-# ============================================================================
-
-
-class NotificationSettingsResponse(BaseModel):
-    """Notification preferences response."""
-
-    email_notifications: bool = True
-    in_app_notifications: bool = True
-    notification_types: dict[str, bool] = Field(default_factory=dict)
-    message: str | None = None
-
-
-class NotificationSettingsUpdate(BaseModel):
-    """Request model for updating notification settings."""
-
-    email_notifications: bool | None = None
-    in_app_notifications: bool | None = None
-    notification_types: dict[str, bool] | None = None
-
-
-# ============================================================================
-# NOTIFICATION TEMPLATE SCHEMAS
-# ============================================================================
-
-
-class NotificationTemplateResponse(BaseModel):
-    """Single notification template response."""
-
-    id: int
-    name: str
-    type: str
-    subject: str
-    body_html: str | None = None
-    body_text: str | None = None
-    variables: list[str] = Field(default_factory=list)
-    is_active: bool = True
-    created_at: datetime
-    updated_at: datetime | None = None
-
-    model_config = {"from_attributes": True}
-
-
-class NotificationTemplateListResponse(BaseModel):
-    """List of notification templates."""
-
-    templates: list[NotificationTemplateResponse] = []
-    message: str | None = None
-
-
-class NotificationTemplateUpdate(BaseModel):
-    """Request model for updating notification template."""
-
-    subject: str | None = Field(None, max_length=200)
-    body_html: str | None = None
-    body_text: str | None = None
-    is_active: bool | None = None
-
-
-# ============================================================================
-# TEST NOTIFICATION SCHEMA
-# ============================================================================
-
-
-class TestNotificationRequest(BaseModel):
-    """Request model for sending test notification."""
-
-    template_id: int | None = Field(None, description="Template to use")
-    email: str | None = Field(None, description="Override recipient email")
-    notification_type: str = Field(
-        default="test", description="Type of notification to send"
-    )
-
-
-# ============================================================================
-# ADMIN ALERT STATISTICS SCHEMA
-# ============================================================================
-
-
-class AlertStatisticsResponse(BaseModel):
-    """Response for alert statistics."""
-
-    total_alerts: int = 0
-    active_alerts: int = 0
-    critical_alerts: int = 0
-    resolved_today: int = 0
+__all__ = [
+    # Response schemas
+    "MessageResponse",
+    "UnreadCountResponse",
+    # Notification schemas
+    "NotificationResponse",
+    "NotificationListResponse",
+    # Settings schemas
+    "NotificationSettingsResponse",
+    "NotificationSettingsUpdate",
+    # Template schemas
+    "NotificationTemplateResponse",
+    "NotificationTemplateListResponse",
+    "NotificationTemplateUpdate",
+    # Test notification
+    "TestNotificationRequest",
+    # Alert statistics
+    "AlertStatisticsResponse",
+]