fix(installer/updater): 修复版本显示和更新流程问题

- 在installer.lua中添加INSTALLER_VERSION常量替代_VERSION
- 更新update.lua中的版本检查流程和用户提示
- 改进updater的界面显示，添加顶部名称栏
- 统一更新确认提示为小写[y/n]
- 将"stage"改为更准确的"step"描述

data/computercraft/lua/rom/update.lua

@@ -9,11 +9,33 @@ if not package.loaded.http then
   io.stderr:write("The HTTP API is disabled and the updater cannot continue.  Please enable the HTTP API in the ComputerCraft configuration and try again.\n")
   return
 end
+term.at(1, 1).clear()
 
-term.at(1,1).clear()
+-- 程序顶部名称栏
+local term = require("term")
+local colors = require("colors")
+-- 保存当前颜色设置
+local old_fg = term.getTextColor()
+local old_bg = term.getBackgroundColor()
+
+-- 设置名称栏颜色并显示
+term.setTextColor(colors.white)
+term.setBackgroundColor(colors.cyan)
+term.at(1, 1).clearLine()
+term.at(1, 1).write("=== LeonOS Updater ===")
+
+-- 恢复颜色设置
+term.setTextColor(old_fg)
+term.setBackgroundColor(old_bg)
+term.at(1, 2)
+-- 只清除顶栏以下的区域
+for y=2, term.getSize() do
+  term.at(1, y).clearLine()
+end
+term.at(1, 2)
 
 textutils.coloredPrint(colors.yellow,
-  "LeonOS Updater (Stage 1)\n===========================")
+  "LeonOS Updater (Step 1)\n===========================")
 
 print("Checking for update...")
 
@@ -36,7 +58,7 @@ if newVersion and (oldVersion ~= newVersion) or (...) == "-f" then
     colors.red, oldVersion, colors.yellow, " -> ", colors.lime,
     newVersion or oldVersion)
 
-  io.write("Apply update? [y/N]: ")
+  io.write("Apply update? [y/n]: ")
   if io.read() ~= "y" then
     textutils.coloredPrint(colors.red, "Not applying update.")
     return
@@ -45,7 +67,7 @@ if newVersion and (oldVersion ~= newVersion) or (...) == "-f" then
   textutils.coloredPrint(colors.green, "Applying update.")
   local handle, err = http.get(base.."updater.lua", nil, true)
   if not handle then
-    error("Failed downloading stage 2: " .. err, 0)
+    error("Failed downloading step 2: " .. err, 0)
   end
 
   local data = handle.readAll()