新增存档面板：组/槽两级列表浏览与删除

src/UI/Panels/SaveSlot.tscn

@@ -4,22 +4,17 @@
 [ext_resource type="LabelSettings" uid="uid://bn06sljdiloor" path="res://resources/save_menu_label_settings.tres" id="2_lm8et"]
 [ext_resource type="Theme" uid="uid://btnjeju2d47x8" path="res://resources/save_menu_button_theme.tres" id="2_m8lv8"]
 
-[node name="SaveSlot" type="Panel" unique_id=815772812]
-anchors_preset = 14
-anchor_top = 0.5
+[node name="SaveSlot" type="PanelContainer" unique_id=270996818]
+anchors_preset = 10
 anchor_right = 1.0
-anchor_bottom = 0.5
+offset_bottom = 50.0
 grow_horizontal = 2
-grow_vertical = 2
+custom_minimum_size = Vector2(0, 50)
+size_flags_horizontal = 3
 script = ExtResource("1_gsy4a")
 
 [node name="HBoxContainer" type="HBoxContainer" parent="." unique_id=1394744552]
-layout_mode = 1
-anchors_preset = 15
-anchor_right = 1.0
-anchor_bottom = 1.0
-grow_horizontal = 2
-grow_vertical = 2
+layout_mode = 2
 
 [node name="SlotIndexLabel" type="Label" parent="HBoxContainer" unique_id=1779842797]
 layout_mode = 2
@@ -35,10 +30,12 @@ size_flags_horizontal = 3
 size_flags_stretch_ratio = 15.0
 
 [node name="SaveNameLabel" type="Label" parent="HBoxContainer/VBoxContainer" unique_id=391910928]
+unique_name_in_owner = true
 layout_mode = 2
 size_flags_vertical = 3
 
 [node name="SaveSlotInfo" type="Label" parent="HBoxContainer/VBoxContainer" unique_id=125642674]
+unique_name_in_owner = true
 layout_mode = 2
 size_flags_vertical = 3
 
@@ -53,3 +50,6 @@ layout_mode = 2
 size_flags_horizontal = 3
 theme = ExtResource("2_m8lv8")
 text = "▶"
+
+[connection signal="button_up" from="HBoxContainer/ButtonDelete" to="." method="_on_button_delete_button_up"]
+[connection signal="button_up" from="HBoxContainer/ButtonLoad" to="." method="_on_button_load_button_up"]