Rewrite price lookup from WebSocket to REST API

Replace unreliable WebSocket connections with on-demand REST API calls
for spot and futures prices. Add cached trading pair list (refreshed
hourly) for symbol validation, and /refresh command for manual updates.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/data/market/future_price.go

@@ -1,64 +1,62 @@
 package market
 
 import (
-	"github.com/adshao/go-binance/v2/futures"
-	"github.com/rs/zerolog/log"
+	"context"
 	"strconv"
+	"time"
+
+	"github.com/rs/zerolog/log"
 )
 
 func (ms *MarketData) GetFuturePrice(symbol string) (float64, float64, int64, bool) {
-	ms.mu.RLock()
-	defer ms.mu.RUnlock()
-	p, ok := ms.futureMarkPrice[symbol]
-	if !ok {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	premiums, err := ms.futuresClient.NewPremiumIndexService().Symbol(symbol).Do(ctx)
+	if err != nil {
+		log.Error().Err(err).Str("symbol", symbol).Msg("Failed to fetch futures premium index")
 		return 0, 0, 0, false
 	}
-	return p, ms.futureFundingRate[symbol], ms.futureNextFundingTime[symbol], true
-}
 
-func (ms *MarketData) StartFutureWsMarkPrice() error {
-	_, _, err := futures.WsAllMarkPriceServe(ms.futureWsMarkPriceHandler, ms.futureWsErrHandler)
+	if len(premiums) == 0 {
+		return 0, 0, 0, false
+	}
+
+	p := premiums[0]
+	markPrice, err := strconv.ParseFloat(p.MarkPrice, 64)
 	if err != nil {
-		return err
+		return 0, 0, 0, false
 	}
-	return nil
-}
 
-func (ms *MarketData) futureWsMarkPriceHandler(event futures.WsAllMarkPriceEvent) {
-	ms.mu.Lock()
-	defer ms.mu.Unlock()
-	for _, priceEvent := range event {
-		price, err := strconv.ParseFloat(priceEvent.MarkPrice, 64)
-		if err != nil {
-			continue
-		}
-
-		fundingRate, err := strconv.ParseFloat(priceEvent.FundingRate, 64)
-		if err != nil {
-			continue
-		}
-
-		ms.futureMarkPrice[priceEvent.Symbol] = price
-		ms.futureFundingRate[priceEvent.Symbol] = fundingRate
-		ms.futureNextFundingTime[priceEvent.Symbol] = priceEvent.NextFundingTime
+	fundingRate, err := strconv.ParseFloat(p.LastFundingRate, 64)
+	if err != nil {
+		fundingRate = 0
 	}
-}
 
-func (ms *MarketData) futureWsErrHandler(err error) {
-	log.Debug().Err(err).Msg("Ws Error. Restart socket")
-	_ = ms.StartFutureWsMarkPrice()
+	return markPrice, fundingRate, p.NextFundingTime, true
 }
 
 func (ms *MarketData) GetAllFundRate() (map[string]float64, map[string]int64) {
-	ms.mu.RLock()
-	defer ms.mu.RUnlock()
-	rates := make(map[string]float64, len(ms.futureFundingRate))
-	for k, v := range ms.futureFundingRate {
-		rates[k] = v
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	premiums, err := ms.futuresClient.NewPremiumIndexService().Do(ctx)
+	if err != nil {
+		log.Error().Err(err).Msg("Failed to fetch all futures premium index")
+		return make(map[string]float64), make(map[string]int64)
 	}
-	times := make(map[string]int64, len(ms.futureNextFundingTime))
-	for k, v := range ms.futureNextFundingTime {
-		times[k] = v
+
+	rates := make(map[string]float64, len(premiums))
+	times := make(map[string]int64, len(premiums))
+
+	for _, p := range premiums {
+		rate, err := strconv.ParseFloat(p.LastFundingRate, 64)
+		if err != nil {
+			continue
+		}
+		rates[p.Symbol] = rate
+		times[p.Symbol] = p.NextFundingTime
 	}
+
 	return rates, times
 }