feat: 算力引擎 Go 后端核心（new-api）

- 统一 OpenAI 兼容 /v1 中继 + 渠道/额度/令牌/流水
- 各领域包：relay 模型网关、model 数据层、controller 管理 API

controller/missing_models.go

@@ -0,0 +1,28 @@
+package controller
+
+import (
+	"net/http"
+
+	"github.com/QuantumNous/new-api/model"
+
+	"github.com/gin-gonic/gin"
+)
+
+// GetMissingModels returns the list of model names that are referenced by channels
+// but do not have corresponding records in the models meta table.
+// This helps administrators quickly discover models that need configuration.
+func GetMissingModels(c *gin.Context) {
+	missing, err := model.GetMissingModels()
+	if err != nil {
+		c.JSON(http.StatusOK, gin.H{
+			"success": false,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"success": true,
+		"data":    missing,
+	})
+}