feat: 添加LGUI库和测试程序

添加一个简单的GUI库(lgui.lua)用于CC Tweaked，包含窗口、按钮、标签和文本框等基础组件
同时添加测试程序(test_lgui.lua)用于演示库的功能
更新安装器版本号至0.3.8 Beta 3 Alpha 2

data/computercraft/lua/rom/programs/test_lgui.lua

@@ -0,0 +1,66 @@
+-- test_lgui.lua - Test script for lgui library
+
+-- Load the GUI library
+local lgui = require("lgui")
+
+-- Create a main window
+local mainWindow = lgui.createWindow(2, 2, 40, 15, "LGUI Test")
+
+-- Add a label
+local titleLabel = lgui.Label:new(2, 2, "LGUI Test Application", 36)
+titleLabel:setAlignment("center")
+titleLabel:setColors(lgui.colors.YELLOW, lgui.colors.BLACK)
+mainWindow:addChild(titleLabel)
+
+-- Add a text field
+local textField = lgui.TextField:new(5, 4, 30)
+textField:setText("Enter your name...")
+textField:setColors(lgui.colors.WHITE, lgui.colors.BLACK)
+mainWindow:addChild(textField)
+
+-- Add a button that shows the text from the text field
+local showButton = lgui.Button:new(5, 6, 15, 3, "Show Text")
+showButton:setColors(lgui.colors.WHITE, lgui.colors.BLUE)
+showButton:setOnClick(function()
+  local text = textField:getText()
+  if text and text ~= "" then
+    resultLabel:setText("You entered: " .. text)
+  else
+    resultLabel:setText("Please enter some text first")
+  end
+end)
+mainWindow:addChild(showButton)
+
+-- Add a button that changes the background color
+local colorButton = lgui.Button:new(22, 6, 15, 3, "Change Color")
+colorButton:setColors(lgui.colors.WHITE, lgui.colors.GREEN)
+local colors = {lgui.colors.RED, lgui.colors.GREEN, lgui.colors.BLUE, lgui.colors.YELLOW}
+local currentColor = 1
+colorButton:setOnClick(function()
+  currentColor = currentColor % #colors + 1
+  mainWindow:setColors(lgui.colors.WHITE, colors[currentColor])
+  mainWindow:requestRedraw()
+end)
+mainWindow:addChild(colorButton)
+
+-- Add a result label
+local resultLabel = lgui.Label:new(5, 10, "", 30)
+resultLabel:setColors(lgui.colors.CYAN, lgui.colors.BLACK)
+mainWindow:addChild(resultLabel)
+
+-- Add an exit button
+local exitButton = lgui.Button:new(15, 12, 12, 3, "Exit")
+exitButton:setColors(lgui.colors.WHITE, lgui.colors.RED)
+exitButton:setOnClick(function()
+  lgui.stop()
+end)
+mainWindow:addChild(exitButton)
+
+-- Start the GUI
+print("Starting LGUI test application...")
+print("Click and drag the window title bar to move the window.")
+print("Type in the text field and click 'Show Text' to see what you entered.")
+print("Click 'Change Color' to change the window background color.")
+print("Click 'Exit' to quit the application.")
+lgui.start()
+print("LGUI test application closed.")