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/en.json

@@ -241,6 +241,11 @@
         "description": "Create and manage your characters, their relationships, and story arcs.",
         "badge": "CHAR"
       },
+      "spells": {
+        "title": "Spell Book",
+        "description": "Create and manage spells, magic systems, and supernatural abilities.",
+        "badge": "SPELL"
+      },
       "items": {
         "title": "Items",
         "description": "Manage important items in your story.",
@@ -548,6 +553,7 @@
     "manageWorlds": "Manage worlds",
     "yourLocations": "Your locations",
     "characters": "Characters",
+    "spells": "Spell Book",
     "objectsList": "Objects list",
     "bookGoals": "Book goals",
     "quillsense": "QuillSense Settings",
@@ -869,6 +875,7 @@
     "world": "Worlds",
     "locations": "Locations",
     "characters": "Characters",
+    "spells": "Spells",
     "objects": "Objects",
     "goals": "Goals",
     "quillsense": "QuillSense"