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/spot_price.go

@@ -1,21 +1,36 @@
 package market
 
 import (
+	"context"
 	"strconv"
+	"time"
 
-	"github.com/adshao/go-binance/v2"
 	"github.com/rs/zerolog/log"
 )
 
 func (ms *MarketData) GetSpotPrice(symbol string) (float64, bool) {
-	ms.mu.RLock()
-	p, ok := ms.spotPrice[symbol]
-	ms.mu.RUnlock()
-	if ok {
-		return p, true
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	prices, err := ms.spotClient.NewListPricesService().Symbol(symbol).Do(ctx)
+	if err != nil {
+		log.Error().Err(err).Str("symbol", symbol).Msg("Failed to fetch spot price")
+		return ms.getAlphaPrice(symbol)
 	}
 
-	// If not found, check if it's an Alpha token
+	if len(prices) == 0 {
+		return ms.getAlphaPrice(symbol)
+	}
+
+	price, err := strconv.ParseFloat(prices[0].Price, 64)
+	if err != nil || price == 0 {
+		return ms.getAlphaPrice(symbol)
+	}
+
+	return price, true
+}
+
+func (ms *MarketData) getAlphaPrice(symbol string) (float64, bool) {
 	if ms.IsAlphaToken(symbol) {
 		if alphaToken, exists := ms.GetAlphaToken(symbol); exists {
 			if price := alphaToken.GetPrice(); price > 0 {
@@ -23,32 +38,5 @@ func (ms *MarketData) GetSpotPrice(symbol string) (float64, bool) {
 			}
 		}
 	}
-
 	return 0, false
 }
-
-func (ms *MarketData) StartSpotWsMarkPrice() error {
-	_, _, err := binance.WsAllMarketsStatServe(ms.spotWsAllMarketsStatHandler, ms.spotWsErrHandler) //.WsAllMarkPriceServe(ms.futureWsMarkPriceHandler, ms.futureWsErrHandler)
-
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-func (ms *MarketData) spotWsAllMarketsStatHandler(event binance.WsAllMarketsStatEvent) {
-	ms.mu.Lock()
-	defer ms.mu.Unlock()
-	for _, priceEvent := range event {
-		price, err := strconv.ParseFloat(priceEvent.LastPrice, 64)
-		if err != nil {
-			continue
-		}
-		ms.spotPrice[priceEvent.Symbol] = price
-	}
-}
-
-func (ms *MarketData) spotWsErrHandler(err error) {
-	log.Debug().Err(err).Msg("Spot Ws Error. Restart socket")
-	_ = ms.StartSpotWsMarkPrice()
-}