Remove Alpha token price caching in spotPrice map

Alpha token prices are now looked up directly from Alpha data instead
of being cached into spotPrice. Remove unused ensureAlphaCacheLoaded
and shouldRefreshAlphaCache functions.

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

internal/data/market/spot_price.go

@@ -15,15 +15,10 @@ func (ms *MarketData) GetSpotPrice(symbol string) (float64, bool) {
 		return p, true
 	}
 
-	// If not found, check if it's an Alpha token and ensure cache is loaded
-	ms.ensureAlphaCacheLoaded()
+	// If not found, check if it's an Alpha token
 	if ms.IsAlphaToken(symbol) {
 		if alphaToken, exists := ms.GetAlphaToken(symbol); exists {
-			price := alphaToken.GetPrice()
-			if price > 0 {
-				ms.mu.Lock()
-				ms.spotPrice[symbol] = price
-				ms.mu.Unlock()
+			if price := alphaToken.GetPrice(); price > 0 {
 				return price, true
 			}
 		}