add notes on labels setup for nginx/pihole sautomation

projects/nginx-proxy-manager/index.md

@@ -32,6 +32,32 @@ configurations.
 {{% include "/srv/configs/docker_compose/nginx-proxy-manager/docker-compose.yaml" %}}
 ```
 
+## Automation (Docker Labels)
+
+To avoid manually configuring Proxy Hosts in the UI (and to keep configuration tightly coupled with the services themselves), I use the `npm-sync` sidecar container. 
+
+This sidecar monitors the Docker socket. When a container spins up with specific labels, `npm-sync` automatically talks to the Nginx Proxy Manager API and creates the Proxy Host. When the container is destroyed, the route is cleaned up.
+
+### How to Auto-Configure a Service
+To expose a new container, simply add the following labels to its `docker-compose.yaml`. You do not need to touch the NPM UI.
+
+```yaml
+services:
+  my-app:
+    image: my-app:latest
+    labels:
+      - "npm.proxy.domains=myapp.wompmacho.com" # The URL
+      - "npm.proxy.port=8080"                   # Internal port the app listens on
+      - "npm.proxy.scheme=http"                 # Usually http or https
+      - "npm.proxy.ssl.force=true"              # Force HTTPS
+      - "npm.proxy.ssl.letsencrypt=true"        # Auto-provision SSL certificate
+```
+
+> [!important] Direct Edits
+> Avoid making direct edits to NPM `.conf` files on the host, as it will desync the database and the Web UI. Always use the Web UI or API-driven automation like `npm-sync`.
+
+## Nginx routing
+
 Nginx gives you that great routing to your internal networked servers. Also
 helps you set up your DNS both inside and outside the network. Can be a little
 confusing at first.