Adds x86-64-v2 microarchitecture as a second build target alongside default. Images tagged with -x86_v2 suffix; GHA cache scoped per arch. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Reviewed-on: #12 Reviewed-by: Leon Hermann <lq@blackhole.local> Co-authored-by: Janis <janis-e@gmx.de> Co-committed-by: Janis <janis-e@gmx.de>