balance: smooth adventurer tiers 11-14 cost and power curves

Tier 11 had a 46x cost spike from tier 10 (28B vs expected ~4B),
and tiers 11-14 were all compressed together with tiny per-step
multipliers rather than the consistent ~7x/~3x pattern used
everywhere else. Redistributed tiers 11-13 to use a steady ~4.3x
cost / ~2.15x CP step, bridging cleanly from tier 10 into the
correct tier 14 anchor (200B / 130K CP → tier 15 at ×7 / ×3).

Closes #103, #104

apps/api/src/data/adventurers.ts

@@ -129,36 +129,36 @@ export const defaultAdventurers: Array<Adventurer> = [
     unlocked:         false,
   },
   {
-    baseCost:         28_000_000_000,
+    baseCost:         2_600_000_000,
     class:            "mage",
-    combatPower:      45_000,
+    combatPower:      13_000,
     count:            0,
-    essencePerSecond: 15,
-    goldPerSecond:    14_000,
+    essencePerSecond: 6,
+    goldPerSecond:    4500,
     id:               "arcane_scholar",
     level:            11,
     name:             "Arcane Scholar",
     unlocked:         false,
   },
   {
-    baseCost:         45_000_000_000,
+    baseCost:         11_000_000_000,
     class:            "rogue",
-    combatPower:      55_000,
+    combatPower:      28_000,
     count:            0,
-    essencePerSecond: 20,
-    goldPerSecond:    18_000,
+    essencePerSecond: 11,
+    goldPerSecond:    9500,
     id:               "shadow_assassin",
     level:            12,
     name:             "Shadow Assassin",
     unlocked:         false,
   },
   {
-    baseCost:         70_000_000_000,
+    baseCost:         47_000_000_000,
     class:            "paladin",
-    combatPower:      80_000,
+    combatPower:      60_000,
     count:            0,
-    essencePerSecond: 22,
-    goldPerSecond:    22_000,
+    essencePerSecond: 20,
+    goldPerSecond:    20_000,
     id:               "dark_templar",
     level:            13,
     name:             "Dark Templar",