Document crossplane alpha render op command

Add Test an operation section to Operations concept documentation showing how to
preview Operations locally using the CLI. Follows same pattern as composition
render documentation with usage examples and output format.

Signed-off-by: Nic Cope <[email protected]>

Author: negz

content/master/operations/operation.md

@@ -475,6 +475,86 @@ Use caution with Operations that change resources managed by other controllers.
 Operations force ownership when applying changes, which can cause conflicts.
 {{</hint>}}
 
+## Test an operation
+
+You can preview the output of any Operation using the Crossplane CLI. You
+don't need a Crossplane control plane to do this. The Crossplane CLI uses Docker
+Engine to run functions.
+
+{{<hint "tip">}}
+See the [Crossplane CLI docs]({{<ref "../cli">}}) to
+learn how to install and use the Crossplane CLI.
+{{< /hint >}}
+
+{{<hint "important">}}
+Running `crossplane alpha render op` requires [Docker](https://www.docker.com).
+{{< /hint >}}
+
+Provide an operation, composition functions, and any required resources to render
+the output locally.
+
+```shell
+crossplane alpha render op operation.yaml functions.yaml --required-resources=ingress.yaml
+```
+
+`crossplane alpha render op` prints the Operation status and any resources the
+operation functions created or modified. It shows what would happen if you
+applied the Operation to a cluster.
+
+```yaml
+---
+# Operation status showing function results
+apiVersion: ops.crossplane.io/v1alpha1
+kind: Operation
+metadata:
+  name: ingress-cert-monitor
+status:
+  conditions:
+  - type: Succeeded
+    status: "True"
+    reason: PipelineSuccess
+  pipeline:
+  - step: check-ingress-certificate
+    output:
+      certificateExpires: "Sep 29 08:34:02 2025 GMT"
+      daysUntilExpiry: 53
+      hostname: google.com
+      ingressName: example-app
+      status: ok
+---
+# Modified Ingress resource with certificate annotations
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  annotations:
+    cert-monitor.crossplane.io/expires: Sep 29 08:34:02 2025 GMT
+    cert-monitor.crossplane.io/days-until-expiry: "53"
+    cert-monitor.crossplane.io/status: ok
+  name: example-app
+  namespace: default
+spec:
+  # ... ingress spec unchanged
+```
+
+Use `--required-resources` to provide resources that your operation functions
+need access to. You can specify multiple files or use glob patterns:
+
+```shell
+# Multiple specific files
+crossplane alpha render op operation.yaml functions.yaml \
+  --required-resources=deployment.yaml,service.yaml,configmap.yaml
+
+# Glob pattern for all YAML files in a directory
+crossplane alpha render op operation.yaml functions.yaml \
+  --required-resources="resources/*.yaml"
+```
+
+{{<hint "tip">}}
+Use the `crossplane alpha render op` command to test your Operations locally
+before deploying them to a cluster. The command helps validate function logic 
+and required resource access patterns.
+{{</hint>}}
+
 ## Best practices
 
 ### Operation-specific practices