[virtualization] bump to v1.11.1

[universal-itengineer]

Summary

Moves the d8 v subcommands off the pinned fix/cli/mute-warnings-during-cobra-init-release-1-6-2
revision and onto the 1.11 line of github.com/deckhouse/virtualization/src/cli.

Draft — test build, not the final pin. The src/cli/v1.11.1 tag does not exist yet
(expected 2026-08-28). Until it does, both modules point at the current release-1.11
head, 6bd3a583. Needs a repin before review.

What changed

• src/cli: v0.0.0-20260411164351-43c8e331b69d → v0.0.0-20260826084353-6bd3a583bc4e
• api: v1.5.1 → v0.15.1-0.20260826084353-6bd3a583bc4e

Both modules move together and point at the same revision. Upstream src/cli/go.mod
declares api as the placeholder v0.0.0-00010101000000-000000000000 and resolves it
through the virtualization repository's go.work, which does not reach consumers — so the
consumer picks the api version, and go mod tidy cannot do it for us. Leaving api at
v1.5.1 fails the build with undefined: v1alpha2.VMOPPhaseSuperseded and
undefined: subv1alpha2.VirtualMachineSession.

The api version number goes down (v1.5.1 → v0.15.1-0...). Expected: the api module
has its own tag line, and the pseudo-version continues api/v0.15.0.

Also drops the stale go.mod comment telling us to move to 1.8.0 "after updating Kubernetes
to 0.34" — k8s.io/* has been on v0.34.8 since #383.

Verification

• task build — passes
• task lint:dev:check — 0 issues
• ./bin/d8 v --help — subcommand list intact, now including migrate, ansible-inventory,
  collect-debug-info, port-forward
• go test ./cmd/... ./internal/... — one failure, TestTokenConfigured/none in
  internal/strongholddiscovery. It reproduces on an unmodified main (a stronghold token
  present in the local environment), so it is not from this change.

Notes

go get for these two modules needs GOPROXY=direct. proxy.golang.org does not serve
arbitrary revisions of the nested src/cli module, and it fails the same way a wrong ref
does, which makes it easy to misdiagnose:

module github.com/deckhouse/virtualization@... found (v1.11.0),
but does not contain package github.com/deckhouse/virtualization/src/cli

The same message appears when passing the branch name instead of a SHA — go get falls back
to the root module. There is no src/cli/v1.11.x tag to use instead; the newest is
src/cli/v1.8.0.

Before merge

• Repin both modules to the v1.11.1 tags once they exist
• Replace the release-1.11 branch head comments in go.mod
• Re-run build, lint and d8 v --help