docs(nx-cloud): document how to set working directory in nx agents (#34033)

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Fixes #

---------

Co-authored-by: Caleb Ukle <caleb@nrwl.io>
Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

Author: 3 people

astro-docs/src/content/docs/reference/Nx Cloud/launch-templates.mdoc

@@ -738,3 +738,20 @@ launch-templates:
           # This is a safer approach to prevent leaking tokens/passwords
           echo "SOME_VALUE: $SOME_VALUE"
 ```
+
+## Nx Workspace in a Subdirectory
+
+If your Nx workspace is in a subdirectory of your repository, set `NX_WORKING_DIRECTORY` in your launch template:
+
+```yaml
+launch-templates:
+  my-template:
+    resource-class: 'docker_linux_amd64/medium'
+    image: 'ubuntu22.04-node20.11-v9'
+    env:
+      NX_WORKING_DIRECTORY: './client'
+    init-steps:
+      # ...
+```
+
+The `install-node-modules` step automatically respects this variable (but can be overridden at the step level if your lockfile is hosted at the root). For other steps, set the working directory manually.

astro-docs/src/content/docs/reference/environment-variables.mdoc

@@ -86,6 +86,7 @@ Similar to the Nx CLI, Nx Cloud also used the `NX_VERBOSE_LOGGING` environment v
 | `NX_CLOUD_NO_TIMEOUTS`                | boolean | Disables the default 10-second timeout for Nx Cloud requests.                                                                                                                                                          |
 | `NX_NO_CLOUD`                         | boolean | If set to `true`, prevents Nx Cloud from being used for the current run. No remote cache will be used. Value cannot be set if using [distributed task execution](/docs/features/ci-features/distribute-task-execution) |
 | `NX_VERBOSE_LOGGING`                  | boolean | Outputs debug information about agents communicating with the main job. Useful for debugging cache misses and on-premises setup issues.                                                                                |
+| `NX_WORKING_DIRECTORY`                | string  | The subdirectory containing your Nx workspace. Set this in your launch template if your Nx workspace is not at the repository root. Only used by Nx Agents.                                                            |
 
 ### Deprecated Nx Cloud Environment Variables