fix: show dice in spell cast card, dedupe Alchemy folders, assign signature spells

- Spell cast card now embeds the TS dice (base + overcast) and damage dice
  instead of posting separate roll messages; Dice So Nice still animates.
- Spell pack Alchemy sub-folders renamed to Transmutacja / Warzenie Eliksirów
  so the label no longer repeats under the Alchemia folder.
- Discipline schema gains signatureSpells (the sheet already bound to it);
  build-packs fills it with each discipline's own spells.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

scripts/parsers/discipline-parser.ts

@@ -148,6 +148,7 @@ export const parseDisciplines: ParserFn = async (ctx: ParserContext): Promise<Pa
         suggestedSkills: SUGGESTED_SKILLS[seed.id] ?? ['magicalAbilities'],
         passiveAbility: '',
         availableSpells: [],
+        signatureSpells: [],
         description,
       },
       description,