feat(admin): integrate Next.js admin panel (admin-next/) from feat/nextjs-admin

- Add admin-next/: full Next.js + Prisma + shadcn admin panel (45 API routes, 76 components)
- docker-compose: tg_shop_admin service (port 3000, shared db/shop.db, prisma), bot talks to it via ADMIN_CHAT_URL=http://tg_shop_admin:3000/api/chat
- tor-proxy now proxies onion admin to tg_shop_admin:3000 (new panel)
- chatbotService: ADMIN_CHAT_URL default = http://tg_shop_admin:3000/api/chat (removed localhost:3100 anachronism)
- .env admin secrets gitignored (admin-next/.env)

admin-next/next.config.ts

@@ -0,0 +1,12 @@
+import type { NextConfig } from "next";
+
+const nextConfig: NextConfig = {
+  output: "standalone",
+  /* config options here */
+  typescript: {
+    ignoreBuildErrors: true,
+  },
+  reactStrictMode: false,
+};
+
+export default nextConfig;