Add early dependency checks and fix packaging

[gursewak1997]

• Check for bwrap/objcopy/systemctl early with clear errors
• Add missing bubblewrap to bcvk.spec
• Document all runtime dependencies

Closes: #250

[gemini-code-assist]

Code Review

This pull request introduces bubblewrap as a mandatory dependency by updating the RPM spec file, the installation documentation, and the runtime binary validation logic. It also refines the documentation for existing prerequisites and adds explanatory comments regarding binary requirements. Review feedback recommends making the objcopy check conditional to prevent unnecessary dependencies for non-UKI images and suggests including qemu-img in the documentation to align with the package specifications.

[cgwalters]

I think this is a dependency in the target system, not the host.

Not going to really hurt to require it on the host, but the original issue in #250 seems to mostly be about requirements in the target container.

So here and elsewhere, we should be clear about which component is required where.

And yes, the architecture is quite tricky with bubblewrap here, so I may be wrong.

[gursewak1997]

You're right. I had the dependency location backwards. The architecture is tricky: we run podman run , and the target image's entrypoint.sh uses bwrap, then run_impl() inside that namespace uses systemctl/objcopy.

Updated now: So the spec now only has true host requirements (podman, qemu-kvm, virtiofsd, openssh-clients for libvirt SSH), and docs clearly separate the two contexts to address the #250 confusion.