feat: major content expansion with essence and crystal sinks

- 6 zones (up from 3): Shadow Marshes, Volcanic Depths, Astral Void
- 18 bosses (up from 4): 3 per zone with zone-based sequential unlock
- 24 quests (up from 9): 3-4 per zone, reorganised by zone
- 15 adventurer tiers (up from 10): Shadow Assassin through Divine Champion
- 28 equipment pieces (up from 12): boss drops + purchasable with essence/crystals
- 24 upgrades (up from 13): crystal-cost upgrades + new adventurer upgrades
- 22 achievements (up from 14): new milestones for bosses, quests, gold, armies
- Purchasable equipment system: buy items directly with essence or crystals
- Crystal-cost upgrades: spend crystals on global and click power boosts
- Zone-based boss progression: defeating a zone's last boss unlocks the next zone

apps/api/src/data/adventurers.ts

@@ -111,4 +111,59 @@ export const DEFAULT_ADVENTURERS: Adventurer[] = [
     count: 0,
     unlocked: false,
   },
+  {
+    id: "shadow_assassin",
+    name: "Shadow Assassin",
+    class: "rogue",
+    level: 11,
+    goldPerSecond: 5_000,
+    essencePerSecond: 6,
+    combatPower: 18_000,
+    count: 0,
+    unlocked: false,
+  },
+  {
+    id: "arcane_scholar",
+    name: "Arcane Scholar",
+    class: "mage",
+    level: 12,
+    goldPerSecond: 14_000,
+    essencePerSecond: 15,
+    combatPower: 45_000,
+    count: 0,
+    unlocked: false,
+  },
+  {
+    id: "void_walker",
+    name: "Void Walker",
+    class: "rogue",
+    level: 13,
+    goldPerSecond: 40_000,
+    essencePerSecond: 35,
+    combatPower: 130_000,
+    count: 0,
+    unlocked: false,
+  },
+  {
+    id: "celestial_guard",
+    name: "Celestial Guard",
+    class: "paladin",
+    level: 14,
+    goldPerSecond: 120_000,
+    essencePerSecond: 100,
+    combatPower: 400_000,
+    count: 0,
+    unlocked: false,
+  },
+  {
+    id: "divine_champion",
+    name: "Divine Champion",
+    class: "warrior",
+    level: 15,
+    goldPerSecond: 400_000,
+    essencePerSecond: 300,
+    combatPower: 1_200_000,
+    count: 0,
+    unlocked: false,
+  },
 ];