feat: content expansion, prestige shop, and offline earnings improvements

- Expand content to 18 zones, 72 bosses, 95 quests, 32 adventurer tiers
- Add prestige shop with 24 runestone upgrades across 5 categories
- Add PrestigeUpgrade type, data files, API routes, and frontend panel
- Fix offline earnings to include equipment and runestone multipliers
- Add offline essence calculation alongside offline gold
- Update OfflineModal to display both gold and essence earned
- Add IDEAS.md for tracking planned features

apps/web/src/api/client.ts

@@ -2,6 +2,8 @@ import type {
   AuthResponse,
   BossChallengeRequest,
   BossChallengeResponse,
+  BuyPrestigeUpgradeRequest,
+  BuyPrestigeUpgradeResponse,
   LoadResponse,
   PrestigeRequest,
   PrestigeResponse,
@@ -77,6 +79,14 @@ export const prestige = async (body: PrestigeRequest): Promise<PrestigeResponse>
     body: JSON.stringify(body),
   });
 
+export const buyPrestigeUpgrade = async (
+  body: BuyPrestigeUpgradeRequest,
+): Promise<BuyPrestigeUpgradeResponse> =>
+  request<BuyPrestigeUpgradeResponse>("/prestige/buy-upgrade", {
+    method: "POST",
+    body: JSON.stringify(body),
+  });
+
 export const getPublicProfile = async (
   discordId: string,
 ): Promise<PublicProfileResponse> =>