Not detecting readiness of CNPG Cluster Resource

### What happened?

I'm using function-auto-ready with function-kcl to create CloudNativePG (CNPG) Cluster resources. The CNPG Cluster resources have the correct `status.conditions` with `type: Ready, status: "True"` when they become healthy, but function-auto-ready is not detecting them as ready.

Currently, I'm forced to hardcode resources as ready using the `krm.kcl.dev/ready = "True"` annotation from function-kcl, but this defeats the purpose - I want resources to only be marked as ready when they actually report ready status conditions.

**Expected behavior:** function-auto-ready should observe the CNPG Cluster resource's status and mark the composed resource as ready when the Cluster reports `type: Ready, status: "True"` in its status.conditions.

**Actual behavior:** The composed resource "postgres-cluster" continuously shows as "not yet ready" even when the underlying CNPG Cluster is in a healthy state with Ready=True condition.

Error message seen:
```
Normal ComposeResources 63s (x1435 over 20h) defined/compositeresourcedefinition.apiextensions.crossplane.io Composed resource "postgres-cluster" is not yet ready
```

### How can we reproduce it?

1. Create a Composition using Pipeline mode with function-kcl and function-auto-ready:

```yaml
apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
name: postgres-abstraction
spec:
compositeTypeRef:
apiVersion: abc.io/v1alpha1
kind: XPostgres
mode: Pipeline
pipeline:
- step: create-resources
functionRef:
name: function-kcl
input:
apiVersion: krm.kcl.dev/v1alpha1
kind: KCLInput
spec:
source: |
oxr = option("params").oxr

cluster = {
apiVersion = "postgresql.cnpg.io/v1"
kind = "Cluster"
metadata = {
name = "${oxr.metadata.name}-pg"
namespace = "database"
annotations = {
"krm.kcl.dev/composition-resource-name" = "postgres-cluster"
"crossplane.io/external-name" = "${oxr.metadata.name}-pg"
}
}
spec = {
instances = 1
imageName = "ghcr.io/cloudnative-pg/postgresql:17.7-system-trixie"
# ... rest of spec
}
}

items = [cluster]

- step: automatically-detect-ready-composed-resources
functionRef:
name: function-auto-ready
```

2. Create an instance of the XR
3. Wait for the CNPG Cluster to become ready (it will have status.conditions with type: Ready, status: "True")
4. Observe that function-auto-ready still reports the composed resource as "not yet ready"

**Actual CNPG Cluster status** (showing it IS ready):
```yaml
status:
conditions:
- lastTransitionTime: "2026-01-14T09:29:02Z"
message: Cluster is Ready
reason: ClusterIsReady
status: "True"
type: Ready
phase: Cluster in healthy state
readyInstances: 1
```

### What environment did it happen in?

- Function version: v0.6.0 (also tested with v0.5.0)
- Crossplane version: Latest
- Kubernetes distribution: K3s (40+ on-premise clusters)
- Other functions in pipeline: function-kcl, function-status-transformer
- CRD: CloudNativePG Cluster (postgresql.cnpg.io/v1)

### Additional Context

I'm not sure if this is:
1. A compatibility issue between function-kcl and function-auto-ready
2. function-auto-ready not properly observing custom resources (CNPG Clusters) in Pipeline mode
3. Missing configuration or annotation needed for function-auto-ready to observe these resources

I tried:
- Adding `crossplane.io/external-name` annotation
- Using `krm.kcl.dev/composition-resource-name` annotation
- Checking that CNPG Clusters expose the standard `Ready` condition

The only workaround is hardcoding `"krm.kcl.dev/ready" = "True"` in the KCL function output, but this marks resources as ready immediately upon creation rather than waiting for actual readiness.