refactor: Reasonix terminal size matches nvimtree (30cols vertical, 10rows horizontal)

lua/keymap.lua

@@ -45,6 +45,8 @@ do
     local term = require('toggleterm.terminal').Terminal:new({
       direction = wide and 'horizontal' or 'vertical',
       cmd = cmd,
+      -- 横屏→高度 10 行；竖屏→宽度 ≈ nvimtree（30 列）
+      size = wide and 10 or math.floor(ui.width * 0.3),
     })
     term:toggle()
   end