Tool windows redesign and the Novel Editor workspace

Tool windows:
- Every editor (scenario, scene builder, map, interactive objects,
  lighting, catalog export) is rebuilt on the interface ToolWindow chrome
  and the denser ToolTheme: header with title/close, status bar, Ctrl+S,
  dirty-state confirmation.
- Shared building blocks in src/Common: ToolUi (rows, buttons, sections),
  CollapsibleSection, FilteredList, ModFileSelector, DragHandle and
  BackgroundCanvas (scene background with pan/zoom).
- The map, interactive and light editors draw on canvases
  (MapEditorCanvas, InteractiveEditorCanvas, LightEditorCanvas) instead of
  one Control "handle" node per object; the *Handle classes are removed.
- Scenario editor: tab data model (TabData), automatic graph layout
  (ScenarioGraphLayout), file tree/info/thumbnail panel updates.
- Services: ModFileService (mod file listing and writing),
  SceneBackgroundService; MapFileService/ModResourceService follow.
- Catalog export: per-language name/description editing.
- Locale (en/ru) regrouped under tools/*; unused keys removed.

Novel Editor:
- collections/novel_editor.json: a "game" whose entry scene is an
  authoring workspace over the novel engine and the story content.
- NovelEditorHub (scenes/novel_editor_hub.tscn) lists every installed
  tool through IToolProvider.AddMenuButton; ToolsInitializer registers it
  as the logical scene "novel_editor".

collections/novel_editor.json

@@ -0,0 +1,50 @@
+{
+  "id": "novel_editor",
+  "kind": "game",
+  "name": "Novel Editor",
+  "author": "ct",
+  "version": "1.0.0",
+  "description": "Authoring workspace instead of a game: opens a screen with every installed editor — scenarios, scenes, maps, interactive objects, lighting, catalog export — over the novel engine and the story content they edit.",
+  "entry": { "scene": "novel_editor" },
+  "tags": ["tools", "editor"],
+  "locale": [
+    { "lang": "en", "name": "Novel Editor", "description": "Authoring workspace instead of a game: opens a screen with every installed editor — scenarios, scenes, maps, interactive objects, lighting, catalog export — over the novel engine and the story content they edit." },
+    { "lang": "ru", "name": "Редактор новелл", "description": "Рабочее место автора вместо игры: открывает экран со всеми установленными редакторами — сценариев, сцен, карт, интерактива, света, экспорта каталога — поверх движка новеллы и сюжета, который они правят." }
+  ],
+  "mechanics": [
+    {
+      "id": "editors",
+      "name": "Editors",
+      "role": "tools",
+      "description": "Editor windows and the launcher screen that lists them.",
+      "locale": [ { "lang": "ru", "name": "Редакторы", "description": "Окна редакторов и стартовый экран со списком." } ],
+      "mods": ["tools>=1"]
+    },
+    {
+      "id": "novel_engine",
+      "name": "Novel engine",
+      "role": "engine",
+      "description": "Scenes, scenarios, dialogs, interactive objects, effects, time and lighting, the world map: what the editors preview and play.",
+      "locale": [ { "lang": "ru", "name": "Движок новеллы", "description": "Сцены, сценарии, диалоги, интерактив, эффекты, время и свет, карта мира: то, что редакторы показывают и проигрывают." } ],
+      "mods": ["visual_novel_core>=1", "base2d>=1", "dialog_base>=1", "interactive_base>=1", "effects_base>=1", "time_base>=1", "map_base>=1"]
+    },
+    {
+      "id": "story",
+      "name": "Story",
+      "role": "content",
+      "description": "The bundled story content to edit: Murakami's line and the starter party.",
+      "locale": [ { "lang": "ru", "name": "Сюжет", "description": "Встроенный сюжет для правки: линия Мураками и стартовая партия." } ],
+      "optional": true,
+      "mods": ["murakami>=1", "starter_party>=1"]
+    },
+    {
+      "id": "validation",
+      "name": "Validation",
+      "role": "tools",
+      "description": "Content validator, the cross-mod resource atlas and the localization key map.",
+      "locale": [ { "lang": "ru", "name": "Проверки", "description": "Валидатор контента, карта ресурсов между модами и карта ключей локализации." } ],
+      "optional": true,
+      "mods": ["validator>=0.1", "resource_atlas>=0.1", "locale_atlas>=0.1"]
+    }
+  ]
+}