fix(installer): 更新安装程序版本至0.3.7 Beta 9

docs(help): 更新about.hlp中的网站链接至新域名
refactor(help): 优化pkg_download_en.hlp的代码块显示格式
feat(imageview): 添加图像加载错误提示和注释说明
style(time): 修复帮助文档格式错误
feat(shell): 添加欢迎界面图形显示
test: 新增imageview和help文档的测试程序

data/computercraft/lua/rom/programs/imageview.lua

@@ -1,4 +1,6 @@
 -- imageview.lua: Image viewer that loads from URL
+-- This program uses paintutils library for image handling (CC Tweaked standard)
+-- There is no 'image' API; we use paintutils.loadImage and paintutils.drawImage
 local http = require("http")
 local paintutils = require("paintutils")
 local term = require("term")
@@ -59,6 +61,7 @@ local function main(args)
 
   if not success then
     print("Error loading image: " .. image)
+  print("Make sure the URL points to a valid image file compatible with CC Tweaked.")
     return
   end