feat(appgui): 添加应用GUI界面支持及包类型管理

新增appgui API用于绘制顶部和底部状态栏，提供一致的UI界面
在package.json中添加type字段区分应用和API包类型
更新安装程序以使用新的appgui界面
修改pkg程序以支持根据包类型安装到不同目录
添加appgui使用文档和演示程序

data/computercraft/lua/rom/apis/appgui.lua

@@ -0,0 +1,94 @@
+-- appgui API for LeonOS
+-- Provides simple topbar and downbar drawing functions
+
+local term = require("term")
+local colors = require("colors")
+local expect = require("cc.expect").expect
+
+local appgui = {}
+
+--- Draws a top bar with the specified text centered
+--- @param text string The text to display in the top bar
+--- @param fgColor number Optional foreground color (default: white)
+--- @param bgColor number Optional background color (default: blue)
+function appgui.topbar(text, fgColor, bgColor)
+  expect(1, text, "string")
+  expect(2, fgColor, "number", "nil")
+  expect(3, bgColor, "number", "nil")
+  
+  -- Default colors
+  fgColor = fgColor or colors.white
+  bgColor = bgColor or colors.blue
+  
+  -- Save current colors
+  local oldFg = term.getTextColor()
+  local oldBg = term.getBackgroundColor()
+  
+  -- Get terminal size
+  local w, h = term.getSize()
+  
+  -- Set colors and position
+  term.setTextColor(fgColor)
+  term.setBackgroundColor(bgColor)
+  term.setCursorPos(1, 1)
+  
+  -- Clear the top line
+  term.clearLine()
+  
+  -- Calculate padding for centered text
+  local padding = math.floor((w - #text) / 2)
+  
+  -- Draw the top bar with centered text
+  term.write(string.rep(" ", padding) .. text .. string.rep(" ", padding))
+  
+  -- Restore original colors
+  term.setTextColor(oldFg)
+  term.setBackgroundColor(oldBg)
+  
+  -- Move cursor below the top bar
+  term.setCursorPos(1, 2)
+end
+
+--- Draws a bottom bar with the specified text centered
+--- @param text string The text to display in the bottom bar
+--- @param fgColor number Optional foreground color (default: white)
+--- @param bgColor number Optional background color (default: blue)
+function appgui.downbar(text, fgColor, bgColor)
+  expect(1, text, "string")
+  expect(2, fgColor, "number", "nil")
+  expect(3, bgColor, "number", "nil")
+  
+  -- Default colors
+  fgColor = fgColor or colors.white
+  bgColor = bgColor or colors.blue
+  
+  -- Save current colors
+  local oldFg = term.getTextColor()
+  local oldBg = term.getBackgroundColor()
+  
+  -- Get terminal size
+  local w, h = term.getSize()
+  
+  -- Set colors and position
+  term.setTextColor(fgColor)
+  term.setBackgroundColor(bgColor)
+  term.setCursorPos(1, h)
+  
+  -- Clear the bottom line
+  term.clearLine()
+  
+  -- Calculate padding for centered text
+  local padding = math.floor((w - #text) / 2)
+  
+  -- Draw the bottom bar with centered text
+  term.write(string.rep(" ", padding) .. text .. string.rep(" ", padding))
+  
+  -- Restore original colors
+  term.setTextColor(oldFg)
+  term.setBackgroundColor(oldBg)
+  
+  -- Move cursor to a safe position
+  term.setCursorPos(1, 1)
+end
+
+return appgui