feat: add titles system with unlock tracking and character sheet display

Titles are earned by reaching milestones (quests, bosses, gold, clicks,
adventurers, guild, prestige, transcendence, apotheosis, achievements,
longevity) and are permanent - never lost on prestige/transcendence/
apotheosis resets. 20 titles available at launch.

Also fixes a pre-existing P2034 write-conflict on the load backfill path
and the exactOptionalPropertyTypes violation in the quest failure handler.

apps/api/prisma/schema.prisma

@@ -21,6 +21,8 @@ model Player {
   guildName         String  @default("")
   guildDescription  String  @default("")
   profileSettings   Json?
+  unlockedTitles    Json?
+  activeTitle       String  @default("")
   createdAt       Float
   lastSavedAt     Float
   totalGoldEarned              Float @default(0)