feat: 添加 Windows 环境变量编辑器 GUI 应用程序

- 基于 IUP GUI 库开发 Windows 环境变量编辑器
- 实现 PATH 变量的加载、编辑、保存功能
- 提供新建、编辑、浏览、删除、上下移动路径等操作
- 添加管理员权限检查，确保系统变量修改权限
- 包含完整的项目构建配置（Makefile）和依赖库

src/callbacks.c

@@ -0,0 +1,160 @@
+#include "callbacks.h"
+#include "globals.h"
+#include "registry.h"
+#include <string.h>
+#include <stdio.h>
+
+// 按钮回调：新建
+int btn_new_cb(Ihandle *self)
+{
+    char buffer[1024] = "";
+    if (IupGetParam("新建环境变量", NULL, NULL, "路径: %s\n", buffer, NULL))
+    {
+        if (strlen(buffer) > 0)
+        {
+            int count = IupGetInt(list_path, "COUNT");
+            count++;
+            IupSetAttributeId(list_path, "", count, buffer);
+            IupSetInt(list_path, "COUNT", count);
+            IupSetInt(list_path, "VALUE", count);
+        }
+    }
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：编辑
+int btn_edit_cb(Ihandle *self)
+{
+    int selected = IupGetInt(list_path, "VALUE");
+    if (selected == 0)
+        return IUP_DEFAULT;
+
+    char *current_val = IupGetAttributeId(list_path, "", selected);
+    char buffer[4096]; // 假设单个路径不超过4096
+    strncpy(buffer, current_val, 4096);
+    buffer[4095] = '\0';
+
+    if (IupGetParam("编辑环境变量", NULL, NULL, "路径: %s\n", buffer, NULL))
+    {
+        if (strlen(buffer) > 0)
+        {
+            IupSetAttributeId(list_path, "", selected, buffer);
+        }
+    }
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：浏览
+int btn_browse_cb(Ihandle *self)
+{
+    Ihandle *filedlg = IupFileDlg();
+    IupSetAttribute(filedlg, "DIALOGTYPE", "DIR");
+    IupSetAttribute(filedlg, "TITLE", "选择目录");
+
+    IupPopup(filedlg, IUP_CENTER, IUP_CENTER);
+
+    if (IupGetInt(filedlg, "STATUS") != -1)
+    {
+        char *value = IupGetAttribute(filedlg, "VALUE");
+        if (value)
+        {
+            int count = IupGetInt(list_path, "COUNT");
+            count++;
+            IupSetAttributeId(list_path, "", count, value);
+            IupSetInt(list_path, "COUNT", count);
+            IupSetInt(list_path, "VALUE", count);
+        }
+    }
+    IupDestroy(filedlg);
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：删除
+int btn_del_cb(Ihandle *self)
+{
+    int selected = IupGetInt(list_path, "VALUE");
+    if (selected == 0)
+        return IUP_DEFAULT;
+
+    IupSetAttribute(list_path, "REMOVEITEM", "SELECTED");
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：上移
+int btn_up_cb(Ihandle *self)
+{
+    int selected = IupGetInt(list_path, "VALUE");
+    if (selected <= 1)
+        return IUP_DEFAULT; // 已经是第一个或未选中
+
+    char *current = IupGetAttributeId(list_path, "", selected);
+    char *prev = IupGetAttributeId(list_path, "", selected - 1);
+
+    // 交换内容
+    char buf_curr[4096], buf_prev[4096];
+    strncpy(buf_curr, current, 4096);
+    buf_curr[4095] = '\0';
+    strncpy(buf_prev, prev, 4096);
+    buf_prev[4095] = '\0';
+
+    IupSetAttributeId(list_path, "", selected, buf_prev);
+    IupSetAttributeId(list_path, "", selected - 1, buf_curr);
+
+    IupSetInt(list_path, "VALUE", selected - 1);
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：下移
+int btn_down_cb(Ihandle *self)
+{
+    int selected = IupGetInt(list_path, "VALUE");
+    int count = IupGetInt(list_path, "COUNT");
+    if (selected == 0 || selected >= count)
+        return IUP_DEFAULT;
+
+    char *current = IupGetAttributeId(list_path, "", selected);
+    char *next = IupGetAttributeId(list_path, "", selected + 1);
+
+    char buf_curr[4096], buf_next[4096];
+    strncpy(buf_curr, current, 4096);
+    buf_curr[4095] = '\0';
+    strncpy(buf_next, next, 4096);
+    buf_next[4095] = '\0';
+
+    IupSetAttributeId(list_path, "", selected, buf_next);
+    IupSetAttributeId(list_path, "", selected + 1, buf_curr);
+
+    IupSetInt(list_path, "VALUE", selected + 1);
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：确定
+int btn_ok_cb(Ihandle *self)
+{
+    save_path();
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：取消
+int btn_cancel_cb(Ihandle *self)
+{
+    IupExitLoop();
+    return IUP_DEFAULT;
+}
+
+// 按钮回调：帮助
+int btn_help_cb(Ihandle *self)
+{
+    IupMessage("使用说明",
+               "1. 本程序用于编辑系统环境变量 PATH。\n"
+               "2. 必须以【管理员身份】运行才能保存更改。\n"
+               "3. 操作说明：\n"
+               "   - 新建：添加新路径到列表末尾。\n"
+               "   - 编辑：修改选中的路径。\n"
+               "   - 浏览：从文件系统选择目录添加。\n"
+               "   - 删除：移除选中的路径。\n"
+               "   - 上移/下移：调整路径优先级。\n"
+               "4. 点击【确定】保存更改并生效。\n"
+               "5. 注意：某些正在运行的程序可能需要重启才能识别新的环境变量。");
+    return IUP_DEFAULT;
+}