refactor: optimize codebase encoding

provider/nofxos/ai500.go

@@ -73,7 +73,7 @@ func (c *Client) fetchAI500() ([]CoinData, error) {
 		return nil, fmt.Errorf("API returned failure status")
 	}
 
-	// 空列表是正常情况，不是错误
+	// Empty list is a normal condition, not an error
 	if len(response.Data.Coins) == 0 {
 		log.Printf("ℹ️  AI500 returned empty coin list (no coins meet criteria currently)")
 		return []CoinData{}, nil

provider/nofxos/netflow.go

@@ -23,7 +23,7 @@ type NetFlowResponse struct {
 		Netflows  []NetFlowPosition `json:"netflows"`
 		Count     int               `json:"count"`
 		Type      string            `json:"type"`      // institution or personal
-		Trade     string            `json:"trade"`     // 合约 or 现货
+		Trade     string            `json:"trade"`     // futures or spot
 		TimeRange string            `json:"time_range"`
 		RankType  string            `json:"rank_type"` // top or low
 		Limit     int               `json:"limit"`