The alpine base images used by the `cannon-configurator` initContainer (`wire-server`
chart) and the `job-done` container (`cassandra-migrations` chart) are no longer
hard-coded. They can now be set via `cannon.configuratorImage.{repository,tag,pullPolicy}`
in the `wire-server` chart and `jobDoneImage.{repository,tag}` in the
`cassandra-migrations` chart.

The default was bumped from `alpine:3.21.3` to `alpine:3.24.1`, since alpine 3.21
reaches end-of-support on 2026-11-01. The local integration stack's `init_vhosts`
container also moved from `alpine/curl:3.14` (an Alpine 3.14 image last published
in 2021) to `alpine/curl:8.21.0`.

Operators who mirror images into a private registry should make sure the new
`alpine:3.24.1` tag is cached, or override `repository` to point at their mirror.

The chart release tooling (`hack/bin/set-wire-server-image-version.sh`,
`hack/bin/set-chart-image-version.sh`) now anchors its version stamping to
`repository: quay.io/wire/` lines instead of matching `tag:` by indentation, so
third-party image tags in `values.yaml` are no longer overwritten with the
wire-server release version.
