fix(deploy): serve under /xll-bi/ prefix and bump host port to 8214

Reverse proxy at demo-ctx.lnh2e.com forwards /xll-bi/* unchanged to the
container, so the container's nginx must match that location and Vite
must build asset URLs under the same prefix — otherwise the SPA shell
returns 404 and the JS/CSS resolve to /assets/* with no handler.

- nginx.conf: rename location /bi/ → /xll-bi/ (and assets sub-location)
- vite.config.ts: set base: '/xll-bi/' so built index.html references
  /xll-bi/assets/*
- docker-compose.yml: 8114 → 8214 to match the upstream the proxy targets

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -4,7 +4,7 @@ services:
   bi:
     image: harbor.lnh2e.com/lingniu-v1/bi:main-0.0.0
     ports:
-      - "8114:80"
+      - "8214:80"
     deploy:
       replicas: 1
       restart_policy: