♻️(backend) use mistral sdk with legacy ai feature

We also want to use the mistral sdk with the legacy AI feature when this
one is configured with the settings. In order to separate bot feature,
they now live in their own module.

src/backend/core/api/serializers.py

@@ -19,7 +19,7 @@ from rest_framework import serializers
 
 from core import choices, enums, models, validators
 from core.services import mime_types
-from core.services.ai_services import AI_ACTIONS
+from core.services.ai_services.legacy import AI_ACTIONS
 from core.services.converter_services import (
     ConversionError,
     Converter,

src/backend/core/api/viewsets.py

@@ -49,7 +49,8 @@ from treebeard.exceptions import InvalidMoveToDescendant
 from core import authentication, choices, enums, models
 from core.api.filters import remove_accents
 from core.services import mime_types
-from core.services.ai_services import AIService
+from core.services.ai_services.blocknote import AIService
+from core.services.ai_services.legacy import get_legacy_ai_service
 from core.services.collaboration_services import CollaborationService
 from core.services.converter_services import (
     ConversionError,
@@ -2133,13 +2134,16 @@ class DocumentViewSet(
         # Check permissions first
         self.get_object()
 
+        if not settings.AI_FEATURE_ENABLED or not settings.AI_FEATURE_LEGACY_ENABLED:
+            raise ValidationError("AI feature is not enabled.")
+
         serializer = serializers.AITransformSerializer(data=request.data)
         serializer.is_valid(raise_exception=True)
 
         text = serializer.validated_data["text"]
         action = serializer.validated_data["action"]
 
-        response = AIService().transform(text, action)
+        response = get_legacy_ai_service().transform(text, action)
 
         return drf.response.Response(response, status=drf.status.HTTP_200_OK)
 
@@ -2161,13 +2165,16 @@ class DocumentViewSet(
         # Check permissions first
         self.get_object()
 
+        if not settings.AI_FEATURE_ENABLED or not settings.AI_FEATURE_LEGACY_ENABLED:
+            raise ValidationError("AI feature is not enabled.")
+
         serializer = self.get_serializer(data=request.data)
         serializer.is_valid(raise_exception=True)
 
         text = serializer.validated_data["text"]
         language = serializer.validated_data["language"]
 
-        response = AIService().translate(text, language)
+        response = get_legacy_ai_service().translate(text, language)
 
         return drf.response.Response(response, status=drf.status.HTTP_200_OK)