feat(sprint5): quest system + arcs + rebalance endurance/damage/xp

Quest system:
  4 entities (quest_arcs, quests, player_quests, player_quest_arcs)
  Arc "Les Marais du Têtard" (4 quêtes narratives)
  3 quêtes standalone répétables (chasse/forge/craft)
  5 achievements liés (quests_completed + quest_arc_completed)
  Event-driven: combat/forge/craft/loot émettent quest.progress
  API: available, active, completed, accept, claim, arcs

Rebalance:
  Endurance coût combat 10→5, regen 6min→3min (20/h), repos 20→10
  Dégâts joueur +3 base (plus de combats de 13 tours au level 1)
  Défaite endurance penalty 50→25
  XP monstres réduite (25→8 Têtard, 130→50 Golem) — quêtes = source principale

src/app.module.ts

@@ -17,6 +17,7 @@ import { AchievementModule } from './achievement/achievement.module';
 import { CommunityModule } from './community/community.module';
 import { HallOfFameModule } from './halloffame/halloffame.module';
 import { ProfileModule } from './profile/profile.module';
+import { QuestModule } from './quest/quest.module';
 import { HealthController } from './common/health.controller';
 
 @Module({
@@ -57,6 +58,7 @@ import { HealthController } from './common/health.controller';
     CommunityModule,
     HallOfFameModule,
     ProfileModule,
+    QuestModule,
   ],
   controllers: [HealthController],
 })