Refactor skill management and marketplace UI for improved functionality

objects/ui/skill_button.tscn

@@ -0,0 +1,16 @@
+[gd_scene load_steps=3 format=3 uid="uid://ceqjwmihj70lt"]
+
+[ext_resource type="Texture2D" uid="uid://cvhoq7aubxlmq" path="res://sprites/ui/magnetic_skill_icon.png" id="1_wnfk3"]
+[ext_resource type="Script" uid="uid://0obbehfd8fki" path="res://scripts/ui/skill_button.gd" id="2_m2732"]
+
+[node name="SkillButton" type="Button"]
+offset_right = 8.0
+offset_bottom = 8.0
+size_flags_horizontal = 3
+size_flags_vertical = 3
+theme_override_font_sizes/font_size = 8
+text = "Fire brick 100"
+icon = ExtResource("1_wnfk3")
+flat = true
+autowrap_mode = 2
+script = ExtResource("2_m2732")