fix: default use global statusline (#133)

lua/avante/init.lua

@@ -194,6 +194,9 @@ function M.setup(opts)
     vim.cmd([[quit]])
   end
 
+  -- use a global statusline
+  vim.opt.laststatus = 3
+
   ---PERF: we can still allow running require("avante").setup() multiple times to override config if users wish to
   ---but most of the other functionality will only be called once from lazy.nvim
   Config.setup(opts)