refactor(utils): 禁用屏幕开关并优化 xset 查找逻辑

- 注释掉所有 BlankOpen/BlankClose 调用，启动不再关屏
- 将 xset 路径查找改为 init + sync.Once 缓存，避免重复执行
- 清理未使用的 utils 导入

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

pkg/utils/blank.go

@@ -3,12 +3,26 @@ package utils
 import (
 	"os"
 	"os/exec"
+	"sync"
 )
 
+var (
+	xsetBin string
+	once    sync.Once
+)
+
+func init() {
+	once.Do(func() {
+		if found, err := exec.LookPath("xset"); err == nil {
+			xsetBin = found
+		}
+	})
+}
+
 // BlankOpen 打开屏幕
 func BlankOpen() {
-	if found, err := exec.LookPath("xset"); err == nil {
-		exec.Command(found, "dpms", "force", "on").Run()
+	if xsetBin != "" {
+		exec.Command(xsetBin, "dpms", "force", "on").Run()
 		return
 	}
 	os.WriteFile("/sys/class/graphics/fb0/blank", []byte("0"), 0644)
@@ -16,8 +30,8 @@ func BlankOpen() {
 
 // BlankClose 关闭屏幕
 func BlankClose() {
-	if found, err := exec.LookPath("xset"); err == nil {
-		exec.Command(found, "dpms", "force", "off").Run()
+	if xsetBin != "" {
+		exec.Command(xsetBin, "dpms", "force", "off").Run()
 		return
 	}
 	os.WriteFile("/sys/class/graphics/fb0/blank", []byte("1"), 0644)