Add forwarding docs to nowhere

Author: addshore

apps/admin/devices/forwarding.md

@@ -77,7 +77,7 @@ The connection defines how and where the data is forwarded to. Some pre-defined
 
 Some connections are provided by the system, which you can use without needing to create your own.
 
-Currently the only system connection that exists is `Lightbug Cloud`.
+Currently two system connections exist: `Lightbug Cloud` and `Nowhere`.
 
 #### Lightbug Cloud
 
@@ -111,6 +111,15 @@ Data can be accessed via Lightbug Cloud as normal, including via the [Cloud App]
 
 ![=500x](https://upload.r2.lb.chasm.cloud/2025/10/chrome_zOCfD9oQ84.png){.center}
 
+#### Nowhere
+
+The `Nowhere` connection allows you to configure device subscriptions as part of forwarding, without actually forwarding data to any external service.
+
+This is useful when you want to:
+
+- Control or test subscriptions, without a data target, or external integration
+- Debug device behavior with different subscription configurations
+
 ### Create a Connection
 
 To create your own connection, click the "New" button, next to the connection selection on the forwarder creation dialog.