Mod naming rule and engine UI in engine mods

Mods are renamed by role (shell2d_base, menu_base, ui_base, live2d_base,
editor_tools, cthangover_story, cthangover_murakami, cthangover_party) and
every reference follows. Engine UI prefabs (dialog, answers, message, game
menu, inventory, map, skills) and their panel entries moved out of the story
mod into the subsystem mods; the card_novel and vn_starter_novel collections
are removed.

scenes/ui/answer_item.tscn

@@ -0,0 +1,30 @@
+[gd_scene format=3 uid="uid://bv80qy227xxee"]
+
+[ext_resource type="Script" uid="uid://dbrnsck0vtfb3" path="res://mods/dialog_base/src/UI/Dialog/AnswerItem.cs" id="1_answeritem"]
+
+[node name="AnswerItem" type="Control" unique_id=1180917887]
+custom_minimum_size = Vector2(0, 50)
+layout_mode = 3
+anchors_preset = 0
+size_flags_horizontal = 3
+size_flags_vertical = 0
+script = ExtResource("1_answeritem")
+
+[node name="Button" type="Button" parent="." unique_id=2087954476]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="TextLabel" type="Label" parent="Button" unique_id=1302827224]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+theme_override_font_sizes/font_size = 22
+horizontal_alignment = 1
+vertical_alignment = 1