fix: serve dist at nginx root, remove /lnbox/ redirect in container

Upstream proxy strips /lnbox/ prefix via proxy_pass, so container nginx
receives requests at /. Old config caused infinite redirect loop.

Dockerfile

@@ -19,13 +19,10 @@ COPY --from=0 /usr/src/app/dist /usr/share/nginx/html/lnbox
 RUN echo "server {\
     listen 80;\
     server_name localhost;\
+    root /usr/share/nginx/html/lnbox;\
+    index index.html;\
     location / {\
-        return 301 /lnbox/;\
-    }\
-    location /lnbox {\
-        alias /usr/share/nginx/html/lnbox;\
-        index index.html index.htm;\
-        try_files \$uri \$uri/ /lnbox/index.html;\
+        try_files \$uri \$uri/ /index.html;\
     }\
 }" > /etc/nginx/conf.d/default.conf