fix: preserve autoAdventurer setting across prestige

The auto-buy adventurers toggle was silently reset to false on every
prestige because it was not included in the list of automation preferences
carried forward into the fresh state. This mirrors the existing handling
for autoBoss and autoQuest.

Closes #156

apps/api/src/services/prestige.ts

@@ -263,7 +263,8 @@ const buildPostPrestigeState = (
      * Preserve automation preferences across prestige — the player explicitly
      * opted into these settings and would not expect them to silently reset.
      */
-    autoBoss: currentState.autoBoss ?? false,
+    autoAdventurer: currentState.autoAdventurer ?? false,
+    autoBoss:       currentState.autoBoss ?? false,
 
     autoQuest:  currentState.autoQuest ?? false,
     // Boss statuses reset for gameplay, but first-kill claimed flag is preserved