feat: add milestone prestige bonuses every 5th prestige

Every 5th prestige awards a scaling runestone windfall:
milestone_number * 25 stones (prestige 5 = 25, 10 = 50, 50 = 250, etc).
Shown in the ascension success message when non-zero.

packages/types/src/interfaces/Api.ts

@@ -58,6 +58,8 @@ export interface BossChallengeResponse {
     crystals: number;
     upgradeIds: string[];
     equipmentIds: string[];
+    /** Runestone bounty awarded for defeating this boss for the very first time */
+    bountyRunestones: number;
   };
   casualties?: Array<{
     adventurerId: string;
@@ -72,6 +74,8 @@ export interface PrestigeRequest {
 export interface PrestigeResponse {
   runestones: number;
   newPrestigeCount: number;
+  /** Bonus runestones awarded for reaching a milestone prestige (every 5th), 0 if not a milestone */
+  milestoneRunestones: number;
 }
 
 export interface BuyPrestigeUpgradeRequest {