Revert "Use UniqueTogetherValidator instead of custom validate function"

This reverts commit 6df035e0f1c6a4be53bca23c839429b4fbaaf7f5.

api/src/backend/api/tests/test_views.py

@@ -5485,8 +5485,16 @@ class TestLighthouseConfigViewSet:
             assert any(field in error["source"]["pointer"] for error in errors)
 
     def test_lighthouse_config_create_duplicate(
-        self, authenticated_client, valid_config_payload, lighthouse_config_fixture
+        self, authenticated_client, valid_config_payload
     ):
+        # Create first config
+        response = authenticated_client.post(
+            reverse("lighthouseconfig-list"),
+            data=valid_config_payload,
+            content_type=API_JSON_CONTENT_TYPE,
+        )
+        assert response.status_code == status.HTTP_201_CREATED
+
         # Try to create second config for same tenant
         response = authenticated_client.post(
             reverse("lighthouseconfig-list"),
@@ -5495,7 +5503,7 @@ class TestLighthouseConfigViewSet:
         )
         assert response.status_code == status.HTTP_400_BAD_REQUEST
         assert (
-            "Lighthouse configuration already exists for this tenant"
+            "AI configuration already exists for this tenant"
             in response.json()["errors"][0]["detail"]
         )
 

api/src/backend/api/v1/serializers.py

@@ -7,7 +7,6 @@ from django.contrib.auth.models import update_last_login
 from django.contrib.auth.password_validation import validate_password
 from drf_spectacular.utils import extend_schema_field
 from jwt.exceptions import InvalidKeyError
-from rest_framework.validators import UniqueTogetherValidator
 from rest_framework_json_api import serializers
 from rest_framework_json_api.serializers import ValidationError
 from rest_framework_simplejwt.exceptions import TokenError
@@ -2182,13 +2181,16 @@ class LighthouseConfigCreateSerializer(RLSSerializer, BaseWriteSerializer):
             "business_context",
             "is_active",
         ]
-        validators = [
-            UniqueTogetherValidator(
-                queryset=LighthouseConfig.objects.all(),
-                fields=["name"],
-                message="Lighthouse configuration already exists for this tenant.",
+
+    def validate(self, attrs):
+        tenant_id = self.context.get("request").tenant_id
+        if LighthouseConfig.objects.filter(tenant_id=tenant_id).exists():
+            raise serializers.ValidationError(
+                {
+                    "tenant_id": "AI configuration already exists for this tenant. Use PUT to update."
+                }
             )
-        ]
+        return super().validate(attrs)
 
     def create(self, validated_data):
         api_key = validated_data.pop("api_key")