feat: initial elysium idle game prototype

Sets up the full monorepo with pnpm workspaces. Includes shared types
package, Hono API with Discord OAuth/JWT auth, Prisma v6 + MongoDB
Atlas, and React + Vite frontend with game loop, five tabs, and
Discord-linked save/load.

apps/api/src/routes/prestige.ts

@@ -0,0 +1,63 @@
+import type { GameState, PrestigeRequest } from "@elysium/types";
+import { Hono } from "hono";
+import { prisma } from "../db/client.js";
+import { authMiddleware } from "../middleware/auth.js";
+import {
+  buildPostPrestigeState,
+  isEligibleForPrestige,
+} from "../services/prestige.js";
+
+export const prestigeRouter = new Hono();
+
+prestigeRouter.use("*", authMiddleware);
+
+prestigeRouter.post("/", async (context) => {
+  const discordId = context.get("discordId") as string;
+  const body = await context.req.json<PrestigeRequest>();
+
+  const characterName = body.characterName?.trim();
+  if (!characterName) {
+    return context.json({ error: "characterName is required" }, 400);
+  }
+
+  const record = await prisma.gameState.findUnique({ where: { discordId } });
+
+  if (!record) {
+    return context.json({ error: "No save found" }, 404);
+  }
+
+  const state = record.state as unknown as GameState;
+
+  if (!isEligibleForPrestige(state)) {
+    return context.json(
+      { error: "Not eligible for prestige — collect 1,000,000 total gold first" },
+      400,
+    );
+  }
+
+  const { newState, newPrestigeData, runestonesEarned } = buildPostPrestigeState(
+    state,
+    characterName,
+  );
+
+  const now = Date.now();
+  await prisma.gameState.update({
+    where: { discordId },
+    data: { state: newState as object, updatedAt: now },
+  });
+
+  await prisma.player.update({
+    where: { discordId },
+    data: {
+      characterName,
+      totalGoldEarned: 0,
+      totalClicks: 0,
+      lastSavedAt: now,
+    },
+  });
+
+  return context.json({
+    runestones: runestonesEarned,
+    newPrestigeCount: newPrestigeData.count,
+  });
+});