Contributor vouch request: kube-state-metrics compatibility scraper

[kalidatuna]

Hi Plural team — I'd like to contribute a kube-state-metrics compatibility scraper under the repository's Contributor Program.

The implementation is already complete on kalidatuna:bounty/kube-state-metrics-compat and was briefly submitted as #4333 before the vouch gate correctly auto-closed it.

Scope:

• new static/compatibilities/kube-state-metrics.yaml generated from kube-state-metrics' official compatibility matrix
• exact app-version → official Prometheus Community Helm chart joins
• scraper registered in the compatibility manifest
• aggregate compatibility data updated
• focused parser, fail-closed, and scraper-wiring tests

Authoritative sources:

• https://github.com/kubernetes/kube-state-metrics/blob/main/README.md#compatibility-matrix
• https://prometheus-community.github.io/helm-charts
• https://github.com/kubernetes/client-go#compatibility-client-go--kubernetes-clusters

Validation already run:

• 9 focused/shared tests passed
• live scraper run against upstream README + Helm index passed
• all three compatibility YAML surfaces pass the repo JSON schema
• aggregate entry matches the individual table exactly
• full compatibility suite: 133 passed, 1 unrelated existing Argo Rollouts fixture failure (2.43.0 expected vs 2.43.1 already in current data)

AI assistance disclosure: the contribution was implemented and verified with OpenAI ChatGPT acting for this GitHub account.

If this contribution is in scope, could a write collaborator please !vouch @kalidatuna so I can reopen #4333 and let the repository checks run?