Feature: Cluster Topology Worker Version Pinning

Tasks:
* [x] Proposal: https://github.com/kubernetes-sigs/cluster-api/pull/13892
* Original requirements: https://github.com/kubernetes-sigs/cluster-api/issues/12466
* [ ] Implementation PR:
* [ ] Check impact on chained upgrades, e.g. min worker version computation
* [ ] Check impact on lifecycle hooks, e.g. lifecycle hooks ignore pinned MD/MP

Related work:
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13433

Feature gate state:
* [ ] Alpha (disabled per default): v1.15 (estimated)
* [ ] Beta (enabled per default): TBD
* [ ] Stable (feature GA): TBD
* [ ] Feature gate removed 1 release later: TBD

Start with the proposal in PR #13892 and the original requirements in issue #12466, then review related work in PR #13433. Trace how chained upgrades compute the minimum worker version and how lifecycle hooks handle pinned MD/MP. Done means an implementation PR addresses both impacts and the feature-gate rollout is defined.

Written by the indexing model from the issue text.