Code Farm economy rebalance: market saturation, infrastructure/defense/cosmetics, mastery track, secondary leaderboards, admin eras, underdog bonus and weekly contracts

Every purchase/upgrade path (new and pre-existing) is now race-safe against concurrent requests via atomic conditional SQL updates.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/api/game/index.py

@@ -36,6 +36,7 @@ def _reset_farm(username, coins=100000):
         get_table("game_plots").delete(farm_uid=farm["uid"])
         get_table("game_quests").delete(farm_uid=farm["uid"])
         get_table("game_farms").delete(uid=farm["uid"])
+    get_table("game_market_ticks").delete()
     farm = store.ensure_farm(user["uid"])
     get_table("game_farms").update({"uid": farm["uid"], "coins": coins}, ["uid"])
     return user