Fix npm app: add schemaVersion, fix internalPort

- Added schemaVersion: 2 to docker-compose.json
- Changed internalPort from env var to number (81)
- Fixes 'invalid hostPort: NaN' error

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/npm/docker-compose.json

@@ -1,10 +1,11 @@
 {
+  "schemaVersion": 2,
   "services": [
     {
       "name": "npm",
       "image": "jc21/nginx-proxy-manager:2.13.5",
       "isMain": true,
-      "internalPort": "${NPM_WEBUI_PORT}",
+      "internalPort": 81,
       "addPorts": [
         {
           "hostPort": "${NPM_HTTP_PORT}",