update environment configuration for local development, enhance database initialization, and improve Nginx routing for admin access

frontend/vite.config.ts

@@ -1,5 +1,14 @@
+import { resolve } from "node:path";
 import { defineConfig } from "vite";
 
 export default defineConfig({
   envDir: "..",
+  build: {
+    rollupOptions: {
+      input: {
+        main: resolve(__dirname, "index.html"),
+        admin: resolve(__dirname, "admin/index.html"),
+      },
+    },
+  },
 });