fix: 修复代码格式、乱码和CORS校验问题

1. 修复tts.go中多余的缩进错误
2. 修复main.go和auth.go中的中文乱码问题，修正日志文本
3. 修复CORS校验逻辑，将origin转为小写后再判断协议前缀
4. 修正auth.go中API密钥未配置时的提示逻辑

middleware/auth.go

@@ -1,4 +1,4 @@
-package middleware
+package middleware
 
 import (
 	"crypto/subtle"
@@ -18,9 +18,9 @@ func InitAPIKeys() {
 		for i, k := range validAPIKeys {
 			validAPIKeys[i] = strings.TrimSpace(k)
 		}
-		log.Printf("已配置 %d 个有效的API密钥", len(validAPIKeys))
+		log.Printf("宸查厤缃?%d 涓湁鏁堢殑API瀵嗛挜", len(validAPIKeys))
 	} else {
-		log.Println("警告: OPENAI_TTS_API_KEY 环境变量未设置，将允许所有请求")
+		log.Println("警告: OPENAI_TTS_API_KEY环境变量未设置，将拒绝所有请求?)
 	}
 }
 

middleware/cors.go

@@ -1,4 +1,4 @@
-package middleware
+package middleware
 
 import (
 	"log"
@@ -53,7 +53,8 @@ func isValidOrigin(origin string) bool {
 	if origin == "" || origin == "null" || origin == "nil" {
 		return false
 	}
-	if !strings.HasPrefix(origin, "http://") && !strings.HasPrefix(origin, "https://") {
+	lowerOrigin := strings.ToLower(origin)
+	if !strings.HasPrefix(lowerOrigin, "http://") && !strings.HasPrefix(lowerOrigin, "https://") {
 		return false
 	}
 	return true