fix: switch admin to subdomain mode and fix frozen-lockfile build

- Remove /admin path prefix (using admin.protdskj.top subdomain instead)
- Change pnpm install to --no-frozen-lockfile for lockfile compatibility
- Simplify admin Nginx config to standard SPA serving

🤖 Generated with [Qoder][https://qoder.com]

docker/nginx/admin.conf

@@ -9,8 +9,8 @@ server {
     gzip on;
     gzip_types text/plain text/css application/json application/javascript text/xml application/xml;
 
-    location /admin/api/ {
-        proxy_pass http://api:3000/api/;
+    location /api/ {
+        proxy_pass http://api:3000;
         proxy_http_version 1.1;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
@@ -18,16 +18,7 @@ server {
         proxy_set_header X-Forwarded-Proto $scheme;
     }
 
-    location /admin/ {
-        alias /usr/share/nginx/html/;
-        try_files $uri $uri/ @admin_spa;
-    }
-
-    location @admin_spa {
-        rewrite ^ /index.html break;
-    }
-
-    location = / {
-        return 301 /admin/;
+    location / {
+        try_files $uri $uri/ /index.html;
     }
 }