fix: preserve messages dispatch config in repository hydration

backend/internal/repository/api_key_repo.go

@@ -167,6 +167,7 @@ func (r *apiKeyRepository) GetByKeyForAuth(ctx context.Context, key string) (*se
 				group.FieldSupportedModelScopes,
 				group.FieldAllowMessagesDispatch,
 				group.FieldDefaultMappedModel,
+				group.FieldMessagesDispatchModelConfig,
 			)
 		}).
 		Only(ctx)
@@ -689,6 +690,7 @@ func groupEntityToService(g *dbent.Group) *service.Group {
 		RequireOAuthOnly:                g.RequireOauthOnly,
 		RequirePrivacySet:               g.RequirePrivacySet,
 		DefaultMappedModel:              g.DefaultMappedModel,
+		MessagesDispatchModelConfig:     g.MessagesDispatchModelConfig,
 		CreatedAt:                       g.CreatedAt,
 		UpdatedAt:                       g.UpdatedAt,
 	}

backend/internal/repository/api_key_repo_integration_test.go

@@ -86,6 +86,45 @@ func (s *APIKeyRepoSuite) TestGetByKey_NotFound() {
 	s.Require().Error(err, "expected error for non-existent key")
 }
 
+func (s *APIKeyRepoSuite) TestGetByKeyForAuth_PreservesMessagesDispatchModelConfig() {
+	user := s.mustCreateUser("getbykey-auth-dispatch@test.com")
+	group, err := s.client.Group.Create().
+		SetName("g-auth-dispatch").
+		SetPlatform(service.PlatformOpenAI).
+		SetStatus(service.StatusActive).
+		SetSubscriptionType(service.SubscriptionTypeStandard).
+		SetRateMultiplier(1).
+		SetAllowMessagesDispatch(true).
+		SetDefaultMappedModel("gpt-5.4").
+		SetMessagesDispatchModelConfig(service.OpenAIMessagesDispatchModelConfig{
+			OpusMappedModel:   "gpt-5.4-nano",
+			SonnetMappedModel: "gpt-5.3-codex",
+			HaikuMappedModel:  "gpt-5.4-mini",
+			ExactModelMappings: map[string]string{
+				"claude-sonnet-4.5": "gpt-5.4-nano",
+			},
+		}).
+		Save(s.ctx)
+	s.Require().NoError(err)
+
+	key := &service.APIKey{
+		UserID:  user.ID,
+		Key:     "sk-getbykey-auth-dispatch",
+		Name:    "Dispatch Key",
+		GroupID: &group.ID,
+		Status:  service.StatusActive,
+	}
+	s.Require().NoError(s.repo.Create(s.ctx, key))
+
+	got, err := s.repo.GetByKeyForAuth(s.ctx, key.Key)
+	s.Require().NoError(err)
+	s.Require().NotNil(got.Group)
+	s.Require().True(got.Group.AllowMessagesDispatch)
+	s.Require().Equal("gpt-5.4", got.Group.DefaultMappedModel)
+	s.Require().Equal("gpt-5.4-nano", got.Group.MessagesDispatchModelConfig.OpusMappedModel)
+	s.Require().Equal("gpt-5.4-nano", got.Group.MessagesDispatchModelConfig.ExactModelMappings["claude-sonnet-4.5"])
+}
+
 // --- Update ---
 
 func (s *APIKeyRepoSuite) TestUpdate() {

backend/internal/repository/api_key_repo_messages_dispatch_unit_test.go

+package repository
+
+import (
+	"context"
+	"testing"
+
+	dbent "github.com/Wei-Shaw/sub2api/ent"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGroupEntityToService_PreservesMessagesDispatchModelConfig(t *testing.T) {
+	group := &dbent.Group{
+		ID:                    1,
+		Name:                  "openai-dispatch",
+		Platform:              service.PlatformOpenAI,
+		Status:                service.StatusActive,
+		SubscriptionType:      service.SubscriptionTypeStandard,
+		RateMultiplier:        1,
+		AllowMessagesDispatch: true,
+		DefaultMappedModel:    "gpt-5.4",
+		MessagesDispatchModelConfig: service.OpenAIMessagesDispatchModelConfig{
+			OpusMappedModel:   "gpt-5.4-nano",
+			SonnetMappedModel: "gpt-5.3-codex",
+			HaikuMappedModel:  "gpt-5.4-mini",
+			ExactModelMappings: map[string]string{
+				"claude-sonnet-4.5": "gpt-5.4-nano",
+			},
+		},
+	}
+
+	got := groupEntityToService(group)
+	require.NotNil(t, got)
+	require.Equal(t, group.MessagesDispatchModelConfig, got.MessagesDispatchModelConfig)
+}
+
+func TestAPIKeyRepository_GetByKeyForAuth_PreservesMessagesDispatchModelConfig_SQLite(t *testing.T) {
+	repo, client := newAPIKeyRepoSQLite(t)
+	ctx := context.Background()
+	user := mustCreateAPIKeyRepoUser(t, ctx, client, "getbykey-auth-dispatch-unit@test.com")
+
+	group, err := client.Group.Create().
+		SetName("g-auth-dispatch-unit").
+		SetPlatform(service.PlatformOpenAI).
+		SetStatus(service.StatusActive).
+		SetSubscriptionType(service.SubscriptionTypeStandard).
+		SetRateMultiplier(1).
+		SetAllowMessagesDispatch(true).
+		SetDefaultMappedModel("gpt-5.4").
+		SetMessagesDispatchModelConfig(service.OpenAIMessagesDispatchModelConfig{
+			OpusMappedModel:   "gpt-5.4-nano",
+			SonnetMappedModel: "gpt-5.3-codex",
+			HaikuMappedModel:  "gpt-5.4-mini",
+			ExactModelMappings: map[string]string{
+				"claude-sonnet-4.5": "gpt-5.4-nano",
+			},
+		}).
+		Save(ctx)
+	require.NoError(t, err)
+
+	key := &service.APIKey{
+		UserID:  user.ID,
+		Key:     "sk-getbykey-auth-dispatch-unit",
+		Name:    "Dispatch Key Unit",
+		GroupID: &group.ID,
+		Status:  service.StatusActive,
+	}
+	require.NoError(t, repo.Create(ctx, key))
+
+	got, err := repo.GetByKeyForAuth(ctx, key.Key)
+	require.NoError(t, err)
+	require.NotNil(t, got.Group)
+	require.Equal(t, group.MessagesDispatchModelConfig, got.Group.MessagesDispatchModelConfig)
+}

backend/internal/repository/group_repo_integration_test.go

@@ -113,6 +113,33 @@ func (s *GroupRepoSuite) TestUpdate() {
 	s.Require().Equal("updated", got.Name)
 }
 
+func (s *GroupRepoSuite) TestGetByID_PreservesMessagesDispatchModelConfig() {
+	group := &service.Group{
+		Name:                  "openai-dispatch",
+		Platform:              service.PlatformOpenAI,
+		RateMultiplier:        1.0,
+		IsExclusive:           false,
+		Status:                service.StatusActive,
+		SubscriptionType:      service.SubscriptionTypeStandard,
+		AllowMessagesDispatch: true,
+		DefaultMappedModel:    "gpt-5.4",
+		MessagesDispatchModelConfig: service.OpenAIMessagesDispatchModelConfig{
+			OpusMappedModel:   "gpt-5.4",
+			SonnetMappedModel: "gpt-5.3-codex",
+			HaikuMappedModel:  "gpt-5.4-mini",
+			ExactModelMappings: map[string]string{
+				"claude-sonnet-4.5": "gpt-5.4-nano",
+			},
+		},
+	}
+
+	s.Require().NoError(s.repo.Create(s.ctx, group))
+
+	got, err := s.repo.GetByID(s.ctx, group.ID)
+	s.Require().NoError(err)
+	s.Require().Equal(group.MessagesDispatchModelConfig, got.MessagesDispatchModelConfig)
+}
+
 func (s *GroupRepoSuite) TestDelete() {
 	group := &service.Group{
 		Name:             "to-delete",