Fix: Invalid app version label when using hash in custom image

[maltesander]

Description

When using custom images like:

---
apiVersion: spark.stackable.tech/v1alpha1
kind: SparkApplication
metadata:
  name: spark-ny-cm
spec:
  sparkImage:
    productVersion: 3.5.6
    custom: oci.stackable.tech/sdp/spark-k8s:3.5.6-stackable25.7.0@sha256:c8b77ba72de6f8ddb99cb484b5ee79c43623cc2514d1448243f7d65d0ef66212
    #custom: oci.stackable.tech/sdp/spark-k8s@sha256:c8b77ba72de6f8ddb99cb484b5ee79c43623cc2514d1448243f7d65d0ef66212

the operator errors out due to creating invalid labels:

2025-08-07T10:52:54.347504Z ERROR app_controller: stackable_operator::logging::controller: Failed to reconcile object controller.name="sparkapplication.spark.stackable.tech" error=reconciler for object SparkApplication.v1alpha1.spark.stackable.tech/spark-ny-cm.default failed error.sources=[failed to build Metadata, failed to set recommended labels, failed to parse value "3.5.2-sha256:15725cf7ee1d648dd81e3bcbf8bcfff8e34d922182d5101abc" of key "app.kubernetes.io/version", value violates kubernetes format]

This is a quick and dirty fix replacing all ":" in the hash_or_tag_image used for creating the label with "-" and parsing it as LabelValue.

This is breaking as the "resolve" method now returns an error.

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added

[sbernauer]

I really like us now using a typed value :)
Only some nits

[Techassi]

Blocking for now, I will come back to this later today.

[sbernauer]

Thanks for fixing the bug!

[Techassi]

One last nit-pick, then ready to go.

[maltesander]

Release note:

Previously, when using custom images in combination with a SHA/Digest like e.g. `oci.stackable.tech/sdp/spark-k8s@sha256:c8b77ba72de6f8ddb99cb484b5ee79c43623cc2514d1448243f7d65d0ef66212`, all operators created invalid labels `app.kubernetes.io/version` for their applied resources. This was fixed by checking and replacing invalid characters in the created labels when a SHA/Digest is involved in the custom image.