feat: 初始提交 LeonOS 实现

添加 LeonOS 的基本实现，包括：
- 核心 API 模块（colors, disk, gps, keys, multishell, parallel, rednet, redstone, settings, vector）
- 命令行程序（about, alias, bg, clear, copy, delete, edit, fg, help, list, lua, mkdir, move, paint, peripherals, programs, reboot, set, shutdown, threads）
- 系统启动脚本和包管理
- 文档（README.md, LICENSE）
- 开发工具（devbin）和更新程序

实现功能：
- 完整的线程管理系统
- 兼容 ComputerCraft 的 API 设计
- 改进的 shell 和命令补全系统
- 多标签终端支持
- 设置管理系统

data/computercraft/lua/rom/startup/90_settings.lua

@@ -0,0 +1,101 @@
+-- setting definitions
+
+local settings = require("settings")
+
+settings.define("list.show_hidden", {
+  description = "Show hidden files in list's output",
+  type = "boolean",
+  default = false
+})
+
+settings.define("bios.compat_mode", {
+  description = "Attempt some LeonOS compatibility by injecting APIs into _G.",
+  type = "boolean",
+  default = false
+})
+
+settings.define("shell.tracebacks", {
+  description = "Show error tracebacks in the shell.",
+  type = "boolean",
+  default = false
+})
+
+settings.define("edit.scroll_offset", {
+  description = "How many lines to keep between the cursor and the screen edge.",
+  type = "number",
+  default = 3
+})
+
+settings.define("edit.force_highlight", {
+  description = "Whether to use the highlighting editor, even on basic computers.",
+  type = "boolean",
+  default = false
+})
+
+settings.define("edit.scroll_factor", {
+  description = "Related to how many lines the editor should jump at a time when scrolling. Determined by term_height/scroll_factor.  Adjust this for performance.",
+  type = "number",
+  default = 8
+})
+
+settings.define("edit.color_separator", {
+  description = "What color separating characters (e.g. ()[];{}) should be.",
+  type = "string",
+  default = "lightBlue"
+})
+
+settings.define("edit.color_operator", {
+  description = "What color operators (e.g. +-/*) should be.",
+  type = "string",
+  default = "lightGray"
+})
+
+settings.define("edit.color_keyword", {
+  description = "What color keywords (e.g. local, for, if) should be.",
+  type = "string",
+  default = "orange"
+})
+
+settings.define("edit.color_boolean", {
+  description = "What color booleans (true/false) should be.",
+  type = "string",
+  default = "purple"
+})
+
+settings.define("edit.color_comment", {
+  description = "What color comments should be.",
+  type = "string",
+  default = "gray"
+})
+
+settings.define("edit.color_global", {
+  description = "What color globals (e.g. print, require) should be.",
+  type = "string",
+  default = "lime"
+})
+
+settings.define("edit.color_string", {
+  description = "What color strings should be.",
+  type = "string",
+  default = "red"
+})
+
+settings.define("edit.color_number", {
+  description = "What color numbers (e.g. 2, 0xF3, 0.42) should be.",
+  type = "string",
+  default = "magenta"
+})
+
+settings.define("bios.restrict_globals", {
+  description = "Disallow global variables",
+  type = "boolean",
+  default = false
+})
+
+settings.define("bios.parallel_startup", {
+  description = "Run startup scripts from /startup in parallel",
+  type = "boolean",
+  default = false
+})
+
+settings.load()