fix: patch adventurer stats on sync so rebalances apply to existing saves

Sync New Content now updates baseCost, class, combatPower, essencePerSecond,
goldPerSecond, level, and name for all existing adventurer entries to match
the current defaults, while preserving count and unlocked state.

Closes #126

packages/types/src/interfaces/api.ts

@@ -4,6 +4,7 @@
  * @license Naomi's Public License
  * @author Naomi Carrigan
  */
+/* eslint-disable max-lines -- API types file grows with each new endpoint */
 import type {
   EquipmentBonus,
   EquipmentRarity,
@@ -468,6 +469,11 @@ interface SyncNewContentResponse {
    */
   adventurersAdded: number;
 
+  /**
+   * Number of existing adventurer entries whose stats were patched to match current defaults.
+   */
+  adventurerStatsPatched: number;
+
   /**
    * Number of upgrades added to the save.
    */