[bmscomp]

Moves every pin to 1.38.0 ahead of the v1.38.0 tag.

• Charts: kates 0.18.1, strimzi-operator 0.4.18, kafka-cluster 1.0.32, connect-cluster 2.1.27, mirror-maker2 0.11.27, kates-chaos 2.4.5, kates-platform 0.8.29
• Also: Litmus experiments, registry pages, server.json, the README action pin, the book's version matrix

Ships #598, #599, #600, #601, #606 and #607. #607 is why this release is needed now: the operator's reconciler PR runs its e2e against the released API, which needs Idempotency-Key, a flat sla and the capabilities list. #608 (the operator workspace) ships nothing: no binary, no image, no chart.

Worth knowing before tagging:

• The image carries migration V29, which runs on upgrade.
• charts/kates goes from 0.15.10 to 0.18.1 on Artifact Hub in one step, because 0.16 to 0.18 never reached a tag. That includes the ACTION REQUIRED entry for bundled PostgreSQL (fix(chart): run the bundled PostgreSQL on Alpine, and refuse a libc switch #601).
• chore(deps): bump strimzi/kafka from 1.3.0-kafka-4.3.1 to 1.3.1-kafka-4.3.2 #609 (Strimzi Kafka 4.3.2) is not included.

Run locally: check-versions.sh, chart_bumps.py and its unit tests, gen-version-matrix.sh --check, gen-chart-table.sh --check, helm lint on kates, strimzi-operator and kates-chaos, check-book-style.sh. The other charts' lint and the release Trivy scan run in CI.