perf(网关): 复用分组上下文减少热路径查询

新增 GetByIDLite 并在网关与 Gemini 选择流程复用上下文 group，避免 COUNT 触发
更新 API key 中间件注入 group 上下文，减少重复查库
补充 gateway/gemini 中间件与仓库层回归测试

测试: make test

backend/internal/server/middleware/api_key_auth.go

@@ -1,11 +1,13 @@
 package middleware
 
 import (
+	"context"
 	"errors"
 	"log"
 	"strings"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 
 	"github.com/gin-gonic/gin"
@@ -91,6 +93,7 @@ func apiKeyAuthWithSubscription(apiKeyService *service.APIKeyService, subscripti
 				Concurrency: apiKey.User.Concurrency,
 			})
 			c.Set(string(ContextKeyUserRole), apiKey.User.Role)
+			setGroupContext(c, apiKey.Group)
 			c.Next()
 			return
 		}
@@ -149,6 +152,7 @@ func apiKeyAuthWithSubscription(apiKeyService *service.APIKeyService, subscripti
 			Concurrency: apiKey.User.Concurrency,
 		})
 		c.Set(string(ContextKeyUserRole), apiKey.User.Role)
+		setGroupContext(c, apiKey.Group)
 
 		c.Next()
 	}
@@ -173,3 +177,14 @@ func GetSubscriptionFromContext(c *gin.Context) (*service.UserSubscription, bool
 	subscription, ok := value.(*service.UserSubscription)
 	return subscription, ok
 }
+
+func setGroupContext(c *gin.Context, group *service.Group) {
+	if group == nil {
+		return
+	}
+	if existing, ok := c.Request.Context().Value(ctxkey.Group).(*service.Group); ok && existing != nil && existing.ID == group.ID {
+		return
+	}
+	ctx := context.WithValue(c.Request.Context(), ctxkey.Group, group)
+	c.Request = c.Request.WithContext(ctx)
+}

backend/internal/server/middleware/api_key_auth_google.go

@@ -63,6 +63,7 @@ func APIKeyAuthWithSubscriptionGoogle(apiKeyService *service.APIKeyService, subs
 				Concurrency: apiKey.User.Concurrency,
 			})
 			c.Set(string(ContextKeyUserRole), apiKey.User.Role)
+			setGroupContext(c, apiKey.Group)
 			c.Next()
 			return
 		}
@@ -102,6 +103,7 @@ func APIKeyAuthWithSubscriptionGoogle(apiKeyService *service.APIKeyService, subs
 			Concurrency: apiKey.User.Concurrency,
 		})
 		c.Set(string(ContextKeyUserRole), apiKey.User.Role)
+		setGroupContext(c, apiKey.Group)
 		c.Next()
 	}
 }

backend/internal/server/middleware/api_key_auth_google_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 
@@ -133,6 +134,69 @@ func TestApiKeyAuthWithSubscriptionGoogle_QueryApiKeyRejected(t *testing.T) {
 	require.Equal(t, "INVALID_ARGUMENT", resp.Error.Status)
 }
 
+func TestApiKeyAuthWithSubscriptionGoogleSetsGroupContext(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	group := &service.Group{
+		ID:       99,
+		Name:     "g1",
+		Status:   service.StatusActive,
+		Platform: service.PlatformGemini,
+	}
+	user := &service.User{
+		ID:          7,
+		Role:        service.RoleUser,
+		Status:      service.StatusActive,
+		Balance:     10,
+		Concurrency: 3,
+	}
+	apiKey := &service.APIKey{
+		ID:     100,
+		UserID: user.ID,
+		Key:    "test-key",
+		Status: service.StatusActive,
+		User:   user,
+		Group:  group,
+	}
+	apiKey.GroupID = &group.ID
+
+	apiKeyService := service.NewAPIKeyService(
+		fakeAPIKeyRepo{
+			getByKey: func(ctx context.Context, key string) (*service.APIKey, error) {
+				if key != apiKey.Key {
+					return nil, service.ErrAPIKeyNotFound
+				}
+				clone := *apiKey
+				return &clone, nil
+			},
+		},
+		nil,
+		nil,
+		nil,
+		nil,
+		&config.Config{RunMode: config.RunModeSimple},
+	)
+
+	cfg := &config.Config{RunMode: config.RunModeSimple}
+	r := gin.New()
+	r.Use(APIKeyAuthWithSubscriptionGoogle(apiKeyService, nil, cfg))
+	r.GET("/v1beta/test", func(c *gin.Context) {
+		groupFromCtx, ok := c.Request.Context().Value(ctxkey.Group).(*service.Group)
+		if !ok || groupFromCtx == nil || groupFromCtx.ID != group.ID {
+			c.JSON(http.StatusInternalServerError, gin.H{"ok": false})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{"ok": true})
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/v1beta/test", nil)
+	req.Header.Set("x-api-key", apiKey.Key)
+	rec := httptest.NewRecorder()
+	r.ServeHTTP(rec, req)
+
+	require.Equal(t, http.StatusOK, rec.Code)
+}
+
 func TestApiKeyAuthWithSubscriptionGoogle_QueryKeyAllowedOnV1Beta(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 

backend/internal/server/middleware/api_key_auth_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 	"github.com/gin-gonic/gin"
@@ -110,6 +111,63 @@ func TestSimpleModeBypassesQuotaCheck(t *testing.T) {
 	})
 }
 
+func TestAPIKeyAuthSetsGroupContext(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	group := &service.Group{
+		ID:       101,
+		Name:     "g1",
+		Status:   service.StatusActive,
+		Platform: service.PlatformAnthropic,
+	}
+	user := &service.User{
+		ID:          7,
+		Role:        service.RoleUser,
+		Status:      service.StatusActive,
+		Balance:     10,
+		Concurrency: 3,
+	}
+	apiKey := &service.APIKey{
+		ID:     100,
+		UserID: user.ID,
+		Key:    "test-key",
+		Status: service.StatusActive,
+		User:   user,
+		Group:  group,
+	}
+	apiKey.GroupID = &group.ID
+
+	apiKeyRepo := &stubApiKeyRepo{
+		getByKey: func(ctx context.Context, key string) (*service.APIKey, error) {
+			if key != apiKey.Key {
+				return nil, service.ErrAPIKeyNotFound
+			}
+			clone := *apiKey
+			return &clone, nil
+		},
+	}
+
+	cfg := &config.Config{RunMode: config.RunModeSimple}
+	apiKeyService := service.NewAPIKeyService(apiKeyRepo, nil, nil, nil, nil, cfg)
+	router := gin.New()
+	router.Use(gin.HandlerFunc(NewAPIKeyAuthMiddleware(apiKeyService, nil, cfg)))
+	router.GET("/t", func(c *gin.Context) {
+		groupFromCtx, ok := c.Request.Context().Value(ctxkey.Group).(*service.Group)
+		if !ok || groupFromCtx == nil || groupFromCtx.ID != group.ID {
+			c.JSON(http.StatusInternalServerError, gin.H{"ok": false})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{"ok": true})
+	})
+
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/t", nil)
+	req.Header.Set("x-api-key", apiKey.Key)
+	router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code)
+}
+
 func newAuthTestRouter(apiKeyService *service.APIKeyService, subscriptionService *service.SubscriptionService, cfg *config.Config) *gin.Engine {
 	router := gin.New()
 	router.Use(gin.HandlerFunc(NewAPIKeyAuthMiddleware(apiKeyService, subscriptionService, cfg)))