add gamestate, doc and fix

core/photo_mode/collectible_gallery.tscn

@@ -0,0 +1,48 @@
+[gd_scene format=3 uid="uid://bvw086glfpcba"]
+
+[ext_resource type="Script" uid="uid://dq3qtcrdnikl7" path="res://core/photo_mode/collectible_gallery.gd" id="1_67tug"]
+
+[node name="CollectibleGallery" type="Control" unique_id=354419843]
+layout_mode = 3
+anchors_preset = 8
+anchor_left = 0.5
+anchor_top = 0.5
+anchor_right = 0.5
+anchor_bottom = 0.5
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_67tug")
+
+[node name="PanelContainer" type="PanelContainer" parent="." unique_id=640179265]
+layout_mode = 1
+anchors_preset = 8
+anchor_left = 0.5
+anchor_top = 0.5
+anchor_right = 0.5
+anchor_bottom = 0.5
+offset_left = -350.0
+offset_top = -350.0
+offset_right = 350.0
+offset_bottom = 350.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="MarginContainer" type="MarginContainer" parent="PanelContainer" unique_id=125147979]
+layout_mode = 2
+theme_override_constants/margin_left = 12
+theme_override_constants/margin_top = 12
+theme_override_constants/margin_right = 12
+theme_override_constants/margin_bottom = 12
+
+[node name="ScrollContainer" type="ScrollContainer" parent="PanelContainer/MarginContainer" unique_id=348576028]
+layout_mode = 2
+draw_focus_border = true
+
+[node name="CollectibleGrid" type="GridContainer" parent="PanelContainer/MarginContainer/ScrollContainer" unique_id=1187865988]
+unique_name_in_owner = true
+layout_mode = 2
+size_flags_horizontal = 6
+size_flags_vertical = 2
+theme_override_constants/h_separation = 12
+theme_override_constants/v_separation = 12
+columns = 3