Add spell management to book settings

- Moved spell-related components to the `book/settings/spells` directory for better organization.
- Added "Spells" as a new tool in book settings and composer sidebar with localization support.
- Integrated spell-related UI elements (`SpellComponent`, `SpellList`, `SpellTagManager`) into settings and sidebars.
- Updated logic to handle enabling/disabling of the spells tool per book.

lib/locales/fr.json

@@ -241,6 +241,11 @@
         "description": "Créez et gérez vos personnages, leurs relations et leurs arcs narratifs.",
         "badge": "CHAR"
       },
+      "spells": {
+        "title": "Livre des sortilèges",
+        "description": "Créez et gérez les sortilèges, systèmes de magie et capacités surnaturelles.",
+        "badge": "SPELL"
+      },
       "items": {
         "title": "Objets",
         "description": "Gérez les objets importants de votre histoire.",
@@ -548,6 +553,7 @@
     "manageWorlds": "Gérer les mondes",
     "yourLocations": "Vos lieux",
     "characters": "Les personnages",
+    "spells": "Livre des sortilèges",
     "objectsList": "Liste des objets",
     "bookGoals": "Objectifs du livre",
     "quillsense": "Parametres QuillSense",
@@ -870,6 +876,7 @@
     "world": "Mondes",
     "locations": "Emplacements",
     "characters": "Personnages",
+    "spells": "Sortilèges",
     "objects": "Objets",
     "goals": "Buts",
     "quillsense": "QuillSense"