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/game.ts

@@ -0,0 +1,62 @@
+import type { GameState, SaveRequest } from "@elysium/types";
+import { Hono } from "hono";
+import { prisma } from "../db/client.js";
+import { authMiddleware } from "../middleware/auth.js";
+import { calculateOfflineGold } from "../services/offlineProgress.js";
+
+export const gameRouter = new Hono();
+
+gameRouter.use("*", authMiddleware);
+
+gameRouter.get("/load", async (context) => {
+  const discordId = context.get("discordId") as string;
+
+  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;
+  const now = Date.now();
+
+  const { offlineGold, offlineSeconds } = calculateOfflineGold(state, now);
+
+  if (offlineGold > 0) {
+    state.resources.gold += offlineGold;
+    state.player.totalGoldEarned += offlineGold;
+  }
+
+  state.lastTickAt = now;
+
+  return context.json({ state, offlineGold, offlineSeconds });
+});
+
+gameRouter.post("/save", async (context) => {
+  const discordId = context.get("discordId") as string;
+  const body = await context.req.json<SaveRequest>();
+
+  if (!body.state) {
+    return context.json({ error: "Missing state in request body" }, 400);
+  }
+
+  const now = Date.now();
+
+  await prisma.player.update({
+    where: { discordId },
+    data: {
+      lastSavedAt: now,
+      totalGoldEarned: body.state.player.totalGoldEarned,
+      totalClicks: body.state.player.totalClicks,
+      characterName: body.state.player.characterName,
+    },
+  });
+
+  await prisma.gameState.upsert({
+    where: { discordId },
+    create: { discordId, state: body.state, updatedAt: now },
+    update: { state: body.state, updatedAt: now },
+  });
+
+  return context.json({ savedAt: now });
+});