feat(gameplay): add versioned SRD rules migration

Co-authored-by: multica-agent <github@multica.ai>

apps/web/server/api/v1/campaigns/[id]/characters/suggest.post.ts

@@ -34,7 +34,7 @@ export default defineEventHandler(async (event) => {
     if (!world) throw createError({ statusCode: 404, statusMessage: 'Campaign world not found.' })
 
     const completion = buildJsonCompletion(useRuntimeConfig(), {
-      system: `You create an original, editable Dungeons & Ground character draft for a private 13+ TTRPG campaign. Adapt archetype, equipment and voice to the supplied genre, but always use STR, DEX, CON, INT, WIS and CHA. Keep an alpha hero grounded: ability scores 7–16, max HP 8–20, Armor Class (AC) 10–16, proficiency 2. Give 2–5 useful starting items and a distinctive persona. Never use protected franchise characters. Return only the requested JSON.`,
+      system: `You create an original, editable Dungeons & Ground character draft for a private 13+ SRD 5.2.1 TTRPG campaign. Adapt archetype, equipment and voice to the supplied genre, but always use STR, DEX, CON, INT, WIS and CHA. Keep an alpha hero grounded: ability scores 7–16, max HP 8–20, Armor Class (AC) 10–16, proficiency 2. Choose exactly four fitting skill proficiencies and two saving throw proficiencies; expertise may contain at most one of the chosen skills. Give 2–5 useful starting items and a distinctive persona. Never use protected franchise characters. Return only the requested JSON.`,
       messages: [{
         role: 'user',
         content: JSON.stringify({