fix(nginx): align id and service name with folder name

- id: nginx-custom -> nginx (must match folder name for Runtipi discovery)
- tipiVersion: 1 -> tipi_version: 2 (correct key name and version)
- Removed min_tipi_version and $schema fields
- Service name: nginx-custom -> nginx

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/nginx/docker-compose.json

@@ -1,9 +1,7 @@
 {
-  "schemaVersion": 2,
-  "$schema": "https://schemas.runtipi.io/dynamic-compose.json",
   "services": [
     {
-      "name": "nginx-custom",
+      "name": "nginx",
       "image": "nginx:latest",
       "isMain": true,
       "internalPort": 80,