fix: apply crystal multiplier to boss rewards, steepen prestige threshold, fix stale upgrade race condition, and fix companion format display

Closes #221
Closes #222
Closes #201
Closes #213

apps/api/src/routes/boss.ts

@@ -205,9 +205,11 @@ bossRouter.post("/challenge", async(context) => {
       boss.status = "defeated";
       boss.currentHp = 0;
 
+      const crystalMult = state.prestige.runestonesCrystalMultiplier ?? 1;
       state.resources.gold = state.resources.gold + boss.goldReward;
       state.resources.essence = state.resources.essence + boss.essenceReward;
-      state.resources.crystals = state.resources.crystals + boss.crystalReward;
+      const crystalAward = boss.crystalReward * crystalMult;
+      state.resources.crystals = state.resources.crystals + crystalAward;
       state.player.totalGoldEarned = state.player.totalGoldEarned + boss.goldReward;
 
       for (const upgradeId of boss.upgradeRewards) {
@@ -323,7 +325,7 @@ bossRouter.post("/challenge", async(context) => {
 
       rewards = {
         bountyRunestones: bountyRunestones,
-        crystals:         boss.crystalReward,
+        crystals:         crystalAward,
         equipmentIds:     boss.equipmentRewards,
         essence:          boss.essenceReward,
         gold:             boss.goldReward,

apps/api/src/routes/game.ts

@@ -546,6 +546,17 @@ const validateAndSanitize = (
       ? previous.prestige
       : incoming.prestige;
 
+  /*
+   * If the DB prestige count is higher than the client's, the client is sending a
+   * stale pre-prestige save. Discard its upgrades (which have purchased: true) in
+   * favour of the DB's post-prestige upgrades (purchased: false) so that upgrade
+   * multipliers cannot persist across prestige via a race-condition auto-save.
+   */
+  const upgrades
+    = incoming.prestige.count < previous.prestige.count
+      ? previous.upgrades
+      : incoming.upgrades;
+
   /*
    * Echoes are only granted server-side via transcendence and can only decrease between
    * saves (spent on echo upgrades). Cap at the previous value to block inflation.
@@ -671,6 +682,7 @@ const validateAndSanitize = (
     prestige,
     quests,
     resources,
+    upgrades,
     ...transcendenceSpread,
     ...apotheosisSpread,
     ...explorationSpread,

apps/api/src/services/prestige.ts

@@ -28,8 +28,8 @@ const maxBaseRunestones = 200;
 
 /**
  * Calculates the gold threshold required for the next prestige.
- * Formula: BASE * (count + 1)^2 — polynomial growth that peaks around prestige 8–10
- * then gets easier as the production multiplier overtakes it.
+ * Formula: BASE * (count + 1)^2.5 — steeper growth to keep late prestiges
+ * meaningful even as the production multiplier scales.
  * @param prestigeCount - The current number of prestiges completed.
  * @param thresholdMultiplier - An optional echo-upgrade multiplier applied to the threshold.
  * @returns The gold amount required to prestige.
@@ -40,7 +40,7 @@ const calculatePrestigeThreshold = (
 ): number => {
   return (
     basePrestigeGoldThreshold
-    * Math.pow(prestigeCount + 1, 2)
+    * Math.pow(prestigeCount + 1, 2.5)
     * thresholdMultiplier
   );
 };