refactor: enforce strict architecture rules and add Pydantic response models

- Update architecture rules to be stricter (API-003 now blocks ALL exception
  raising in endpoints, not just HTTPException)
- Update get_current_vendor_api dependency to guarantee token_vendor_id presence
- Remove redundant _get_vendor_from_token helpers from all vendor API files
- Move vendor access validation to service layer methods
- Add Pydantic response models for media, notification, and payment endpoints
- Add get_active_vendor_by_code service method for public vendor lookup
- Add get_import_job_for_vendor service method with vendor validation
- Update validation script to detect exception raising patterns in endpoints

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

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

app/api/v1/admin/notifications.py

@@ -21,7 +21,11 @@ from models.schema.admin import (
     PlatformAlertCreate,
     PlatformAlertListResponse,
     PlatformAlertResolve,
-    PlatformAlertResponse,
+)
+from models.schema.notification import (
+    AlertStatisticsResponse,
+    MessageResponse,
+    UnreadCountResponse,
 )
 
 router = APIRouter(prefix="/notifications")
@@ -49,17 +53,17 @@ def get_notifications(
     )
 
 
-@router.get("/unread-count")
+@router.get("/unread-count", response_model=UnreadCountResponse)
 def get_unread_count(
     db: Session = Depends(get_db),
     current_admin: User = Depends(get_current_admin_api),
 ):
     """Get count of unread notifications."""
     # TODO: Implement
-    return {"unread_count": 0}
+    return UnreadCountResponse(unread_count=0)
 
 
-@router.put("/{notification_id}/read")
+@router.put("/{notification_id}/read", response_model=MessageResponse)
 def mark_as_read(
     notification_id: int,
     db: Session = Depends(get_db),
@@ -67,17 +71,17 @@ def mark_as_read(
 ):
     """Mark notification as read."""
     # TODO: Implement
-    return {"message": "Notification marked as read"}
+    return MessageResponse(message="Notification marked as read")
 
 
-@router.put("/mark-all-read")
+@router.put("/mark-all-read", response_model=MessageResponse)
 def mark_all_as_read(
     db: Session = Depends(get_db),
     current_admin: User = Depends(get_current_admin_api),
 ):
     """Mark all notifications as read."""
     # TODO: Implement
-    return {"message": "All notifications marked as read"}
+    return MessageResponse(message="All notifications marked as read")
 
 
 # ============================================================================
@@ -101,19 +105,19 @@ def get_platform_alerts(
     )
 
 
-@router.post("/alerts", response_model=PlatformAlertResponse)
+@router.post("/alerts", response_model=MessageResponse)
 def create_platform_alert(
     alert_data: PlatformAlertCreate,
     db: Session = Depends(get_db),
     current_admin: User = Depends(get_current_admin_api),
 ):
     """Create new platform alert (manual)."""
-    # TODO: Implement
+    # TODO: Implement - return PlatformAlertResponse when service is ready
     logger.info(f"Admin {current_admin.username} created alert: {alert_data.title}")
-    return {}
+    return MessageResponse(message="Platform alert creation coming soon")
 
 
-@router.put("/alerts/{alert_id}/resolve")
+@router.put("/alerts/{alert_id}/resolve", response_model=MessageResponse)
 def resolve_platform_alert(
     alert_id: int,
     resolve_data: PlatformAlertResolve,
@@ -123,19 +127,19 @@ def resolve_platform_alert(
     """Resolve platform alert."""
     # TODO: Implement
     logger.info(f"Admin {current_admin.username} resolved alert {alert_id}")
-    return {"message": "Alert resolved successfully"}
+    return MessageResponse(message="Alert resolved successfully")
 
 
-@router.get("/alerts/stats")
+@router.get("/alerts/stats", response_model=AlertStatisticsResponse)
 def get_alert_statistics(
     db: Session = Depends(get_db),
     current_admin: User = Depends(get_current_admin_api),
 ):
     """Get alert statistics for dashboard."""
     # TODO: Implement
-    return {
-        "total_alerts": 0,
-        "active_alerts": 0,
-        "critical_alerts": 0,
-        "resolved_today": 0,
-    }
+    return AlertStatisticsResponse(
+        total_alerts=0,
+        active_alerts=0,
+        critical_alerts=0,
+        resolved_today=0,
+    )