feat: add admin dashboard with sidebar navigation and stats overview

Replace placeholder panel with a full dashboard landing page showing
bot stats, leaderboards, and recent events from /api/stats. Add
sidebar navigation with placeholder pages for Users, Items, Classes,
Quests, Lootdrops, Moderation, Transactions, and Settings. Update
theme to match Aurora design guidelines.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

panel/vite.config.ts

@@ -1,9 +1,15 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
 import tailwindcss from "@tailwindcss/vite";
+import path from "path";
 
 export default defineConfig({
   plugins: [react(), tailwindcss()],
+  resolve: {
+    alias: {
+      "@": path.resolve(__dirname, "./src"),
+    },
+  },
   server: {
     port: 5173,
     proxy: {