refactor: 把 /derivatives 的多源编排从 controller 搬进 usecase

为什么：原 controller handler 在 HTTP 层同时承担了 4 项 usecase 职责
（多源拼装、错误降级策略、limit 硬编码、响应结构组装），违反了
"controller 只做参数解析 + 调用 + 序列化" 的边界。等后续给衍生品加
缓存 / taker volume / 数据质量字段时，HTTP 层会持续变厚。

改动：
- 新增 internal/usecase/market_query.go: MarketQueryUsecase.GetDerivatives()
  并发拉 current funding/OI + 串行查历史 + 错误聚合为 warnings 返回
- /derivatives handler 退化到 4 行；MarketDeps / restapi.Deps 同步收窄
- /klines 保持直查 KlineRepo（thin query，G11 例外）
- 新增 G11 守卫：grep "FundingRepo|OIRepo|LSRepo|TakerRepo" internal/controller

破坏性 API 变更（/derivatives 响应）：
- 删除 funding.error / openInterest.error
- 新增顶层 warnings: []string
顶层 symbol / funding / openInterest / longShortRatio / takerBuySellVolume 保持。

harness 同步：
- AGENTS.md §6 加 G11 grep
- ai/project-map.md 加 market_query.go + /derivatives 数据流分支
- ai/task-templates.md T6 加"破坏性变体"分支（本次重构暴露了原假设过严）
- ai/harness-health.md W1 记一次轻量验证 + 守卫数 10→11

验收: go build / go vet / G6 grep / G11 grep 全绿。

internal/app/app.go

@@ -58,6 +58,13 @@ func Run(cfg *config.Config, log *slog.Logger) error {
 		log,
 	)
 
+	queryUC := usecase.NewMarketQueryUsecase(
+		binanceClient,
+		fundingRepo,
+		oiRepo,
+		lsRepo,
+	)
+
 	collector := worker.NewCollector(worker.Deps{
 		MarketData:  binanceClient,
 		Derivatives: binanceClient,
@@ -90,12 +97,9 @@ func Run(cfg *config.Config, log *slog.Logger) error {
 	restapi.Register(fiberApp, restapi.Deps{
 		Logger:        log,
 		MarketContext: contextUC,
+		MarketQuery:   queryUC,
 		MarketData:    binanceClient,
-		Derivatives:   binanceClient,
 		KlineRepo:     klineRepo,
-		FundingRepo:   fundingRepo,
-		OIRepo:        oiRepo,
-		LSRepo:        lsRepo,
 	})
 
 	listenErr := make(chan error, 1)

internal/controller/restapi/router.go

@@ -11,14 +11,11 @@ import (
 )
 
 type Deps struct {
-	Logger         *slog.Logger
-	MarketContext  *usecase.MarketContextUsecase
-	MarketData     usecase.MarketDataProvider
-	Derivatives    usecase.DerivativesProvider
-	KlineRepo      usecase.KlineRepository
-	FundingRepo    usecase.FundingRepository
-	OIRepo         usecase.OpenInterestRepository
-	LSRepo         usecase.LongShortRatioRepository
+	Logger        *slog.Logger
+	MarketContext *usecase.MarketContextUsecase
+	MarketQuery   *usecase.MarketQueryUsecase
+	MarketData    usecase.MarketDataProvider
+	KlineRepo     usecase.KlineRepository
 }
 
 func Register(app *fiber.App, deps Deps) {
@@ -29,11 +26,8 @@ func Register(app *fiber.App, deps Deps) {
 	v1.RegisterHealth(api)
 	v1.RegisterMarket(api, v1.MarketDeps{
 		MarketContext: deps.MarketContext,
+		MarketQuery:   deps.MarketQuery,
 		MarketData:    deps.MarketData,
-		Derivatives:   deps.Derivatives,
 		KlineRepo:     deps.KlineRepo,
-		FundingRepo:   deps.FundingRepo,
-		OIRepo:        deps.OIRepo,
-		LSRepo:        deps.LSRepo,
 	})
 }

internal/controller/restapi/v1/market_routes.go

@@ -6,18 +6,14 @@ import (
 
 	"github.com/gofiber/fiber/v2"
 
-	"cryptoHermes/internal/entity"
 	"cryptoHermes/internal/usecase"
 )
 
 type MarketDeps struct {
 	MarketContext *usecase.MarketContextUsecase
+	MarketQuery   *usecase.MarketQueryUsecase
 	MarketData    usecase.MarketDataProvider
-	Derivatives   usecase.DerivativesProvider
 	KlineRepo     usecase.KlineRepository
-	FundingRepo   usecase.FundingRepository
-	OIRepo        usecase.OpenInterestRepository
-	LSRepo        usecase.LongShortRatioRepository
 }
 
 var allowedIntervals = map[string]bool{
@@ -80,39 +76,18 @@ func RegisterMarket(r fiber.Router, d MarketDeps) {
 			return fiber.NewError(fiber.StatusBadRequest, "symbol is required")
 		}
 
-		fundCur, ferr := d.Derivatives.GetCurrentFunding(c.UserContext(), symbol)
-		oiCur, oerr := d.Derivatives.GetCurrentOpenInterest(c.UserContext(), symbol)
-
-		fundHist, _ := d.FundingRepo.FindRecent(c.UserContext(), symbol, 100)
-		oiHist, _ := d.OIRepo.FindRecent(c.UserContext(), symbol, period, 200)
-		globalLS, _ := d.LSRepo.FindRecent(c.UserContext(), symbol, period, entity.RatioTypeGlobalAccount, 200)
-		topLS, _ := d.LSRepo.FindRecent(c.UserContext(), symbol, period, entity.RatioTypeTopTraderPosition, 200)
-
-		resp := fiber.Map{
-			"symbol": symbol,
-			"funding": fiber.Map{
-				"current": fundCur,
-				"history": fundHist,
-				"error":   errString(ferr),
-			},
-			"openInterest": fiber.Map{
-				"current": oiCur,
-				"history": oiHist,
-				"error":   errString(oerr),
-			},
-			"longShortRatio": fiber.Map{
-				"global":            globalLS,
-				"topTraderPosition": topLS,
-			},
-			"takerBuySellVolume": []any{},
+		bundle, warnings, err := d.MarketQuery.GetDerivatives(c.UserContext(), symbol, period)
+		if err != nil {
+			return fiber.NewError(fiber.StatusInternalServerError, err.Error())
 		}
-		return c.JSON(resp)
+
+		return c.JSON(fiber.Map{
+			"symbol":             symbol,
+			"funding":            bundle.Funding,
+			"openInterest":       bundle.OpenInterest,
+			"longShortRatio":     bundle.LongShortRatio,
+			"takerBuySellVolume": bundle.TakerBuySellVolume,
+			"warnings":           warnings,
+		})
 	})
 }
-
-func errString(e error) string {
-	if e == nil {
-		return ""
-	}
-	return e.Error()
-}

internal/usecase/market_query.go

@@ -0,0 +1,113 @@
+package usecase
+
+import (
+	"context"
+	"sync"
+
+	"golang.org/x/sync/errgroup"
+
+	"cryptoHermes/internal/entity"
+)
+
+const (
+	derivativesFundingHistoryLen = 100
+	derivativesOIHistoryLen      = 200
+	derivativesLongShortLen      = 200
+)
+
+type MarketQueryUsecase struct {
+	derivatives DerivativesProvider
+	fundingRepo FundingRepository
+	oiRepo      OpenInterestRepository
+	lsRepo      LongShortRatioRepository
+}
+
+func NewMarketQueryUsecase(
+	derivatives DerivativesProvider,
+	fundingRepo FundingRepository,
+	oiRepo OpenInterestRepository,
+	lsRepo LongShortRatioRepository,
+) *MarketQueryUsecase {
+	return &MarketQueryUsecase{
+		derivatives: derivatives,
+		fundingRepo: fundingRepo,
+		oiRepo:      oiRepo,
+		lsRepo:      lsRepo,
+	}
+}
+
+func (u *MarketQueryUsecase) GetDerivatives(ctx context.Context, symbol, period string) (*entity.DerivativesBundle, []string, error) {
+	var (
+		currentFund *entity.FundingRate
+		currentOI   *entity.OpenInterest
+		warnMu      sync.Mutex
+		warnings    []string
+	)
+	addWarn := func(w string) {
+		warnMu.Lock()
+		warnings = append(warnings, w)
+		warnMu.Unlock()
+	}
+
+	g, gctx := errgroup.WithContext(ctx)
+	g.Go(func() error {
+		f, err := u.derivatives.GetCurrentFunding(gctx, symbol)
+		if err != nil {
+			addWarn("current funding fetch failed: " + err.Error())
+			return nil
+		}
+		currentFund = f
+		return nil
+	})
+	g.Go(func() error {
+		oi, err := u.derivatives.GetCurrentOpenInterest(gctx, symbol)
+		if err != nil {
+			addWarn("current OI fetch failed: " + err.Error())
+			return nil
+		}
+		currentOI = oi
+		return nil
+	})
+	_ = g.Wait()
+
+	fundingHist, err := u.fundingRepo.FindRecent(ctx, symbol, derivativesFundingHistoryLen)
+	if err != nil {
+		addWarn("funding history query failed: " + err.Error())
+	}
+
+	oiHist, err := u.oiRepo.FindRecent(ctx, symbol, period, derivativesOIHistoryLen)
+	if err != nil {
+		addWarn("OI history query failed: " + err.Error())
+	}
+
+	globalLS, err := u.lsRepo.FindRecent(ctx, symbol, period, entity.RatioTypeGlobalAccount, derivativesLongShortLen)
+	if err != nil {
+		addWarn("global long/short query failed: " + err.Error())
+	}
+
+	topLS, err := u.lsRepo.FindRecent(ctx, symbol, period, entity.RatioTypeTopTraderPosition, derivativesLongShortLen)
+	if err != nil {
+		addWarn("top trader position long/short query failed: " + err.Error())
+	}
+
+	bundle := &entity.DerivativesBundle{
+		Funding: entity.FundingBundle{
+			Current: currentFund,
+			History: fundingHist,
+		},
+		OpenInterest: entity.OpenInterestBundle{
+			Current: currentOI,
+			History: oiHist,
+		},
+		LongShortRatio: entity.LongShortBundle{
+			Global:            globalLS,
+			TopTraderPosition: topLS,
+		},
+		TakerBuySellVolume: []entity.TakerBuySellVolume{},
+	}
+
+	if warnings == nil {
+		warnings = []string{}
+	}
+	return bundle, warnings, nil
+}