docs/design-decisions: D-002 drop vault from OpenStack-core channel row ...

Vault uses 1.8/stable per the Canonical charm delivery table, not the
               2024.1/stable OpenStack-core track. The bundle.yaml already reflects
               this; the design-decisions D-002 description had a stale token.

Update design doc ...

docs: D-002 hacluster row added + D-007 driver pin corrected

D-002: add hacluster | 2.4/stable row (Canonical Charm Delivery table,
       verified against Charmhub 2026-05-22). Update Verification
       source paragraph with rev confirmations.

D-007: Layer B driver pin stackhpc/magnum-capi-helm v0.13.0 →
       openstack/magnum-capi-helm 1.1.0 from PyPI. stackhpc fork
       archived Dec 2024; canonical project moved to opendev/PyPI.
       1.1.0 is last Caracal-cycle release. Note ASCII-only conf.d.
       Add explicit supersedes note for old pin.

Updated scope

Initial Upload