feat(k8s): 新增 core 真应用(前端+Django API+Celery worker)构建与部署

- core/frontend: Vite 多阶段镜像 + nginx 同源反代 /api,/admin,/static(零 CORS)
- core/backend: Django gunicorn 镜像 + entrypoint(自动 migrate/collectstatic)+ WhiteNoise
- k8s/core: api/worker/web Deployment+Service + ingress(airshelf-web.airlabs.art)
- workflow: 追加 core 前后端 build/push,从 core/backend/.env 套生产覆盖生成 env Secret 后部署
- .gitignore 放行 core/backend/.env;.env 白名单加入 airshelf-web 域名
- 含前端 WIP 还原改动

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/frontend/src/main.tsx

@@ -3,5 +3,12 @@ import { App } from "./App";
 import "./styles.css";
 import "./design-restraint.css";
 import "./exact-pages.css";
+import "./account-page.css";
+import "./product-detail-page.css";
+import "./team-page.css";
+import "./pipeline-page.css";
+import "./projects-page.css";
+import "./products-page.css";
+import "./library-page.css";
 
 createRoot(document.getElementById("root")!).render(<App />);