more layout dummy properties

samples/bin/library/scripts/emmy/components/layout.lua

@@ -14,6 +14,15 @@ local layout = {
 
     ---@type layout_modes
     mode = layout.modes.vertical,
+
+    ---@type layout_valigns
+    valign = layout.valigns.center,
+
+    ---@type layout_haligns
+    halign = layout.haligns.center,
+
+    ---@type number
+    spacing = 0.0
 }
 
 ---@class layout_modes
@@ -22,6 +31,20 @@ layout.modes = {
     horizontal = "horizontal"
 }
 
+---@class layout_valigns
+layout.valigns = {
+    top = "top",
+    center = "center",
+    bottom = "bottom"
+}
+
+---@class layout_haligns
+layout.haligns = {
+    left = "left",
+    center = "center",
+    right = "right"
+}
+
 ---@overload fun(self: layout)
 ---@param self layout
 function layout.enable(self) end