[optimized] 代码优化：清理死代码、修复竞态条件与空参数安全问题

- 删除 backup() 中的调试 echo 残留
- 删除被注释的死代码行
- 修复 backup_wifi rm -rf 空参数安全问题
- 重写 start.sh 逻辑，优化配置生成流程
- 重构 kill_Serve 使用 mkdir 原子锁替代 PID 文件

start.sh

@@ -1,9 +1,16 @@
 #!/system/bin/sh
-if [ -f "${0%/*}/tools/tools.sh" ]; then
-    MODDIR="${0%/*}"
-    conf_path="${0%/*}/backup_settings.conf"
-    [ ! -f "${0%/*}/backup_settings.conf" ] && . "${0%/*}/tools/tools.sh"
-else
-    echo "${0%/*}/tools/tools.sh遺失"
+if [ ! -f "${0%/*}/tools/tools.sh" ]; then
+	echo "${0%/*}/tools/tools.sh遺失"
+	exit 1
 fi
+
+MODDIR="${0%/*}"
+conf_path="${0%/*}/backup_settings.conf"
+
+# 若配置文件不存在，啟動腳本自動生成默認配置後退出
+if [ ! -f "$conf_path" ]; then
+	. "${0%/*}/tools/tools.sh"
+	exit 0
+fi
+
 . "${0%/*}/tools/tools.sh" | tee "${0%/*}/log_$(date +%Y-%m-%d_%H-%M).txt"