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/web/src/components/game/ClickArea.tsx

@@ -0,0 +1,25 @@
+import { useGame } from "../../context/GameContext.js";
+import { calculateClickPower } from "../../engine/tick.js";
+
+export const ClickArea = (): React.JSX.Element => {
+  const { state, handleClick } = useGame();
+
+  if (!state) return <div className="click-area-placeholder" />;
+
+  const clickPower = calculateClickPower(state);
+
+  return (
+    <section className="click-area">
+      <h2>Guild Hall</h2>
+      <button
+        className="click-button"
+        onClick={handleClick}
+        type="button"
+        aria-label={`Click to earn ${clickPower.toFixed(1)} gold`}
+      >
+        ⚔️
+      </button>
+      <p className="click-power">+{clickPower.toFixed(1)} gold per click</p>
+    </section>
+  );
+};