Remove obsolete NVX virtio-fs prototype and repro workflow #9565

Summary

Remove the throwaway NVX/OpenVMM patch-carrying prototype merged in #9027 now that the complete live virtio-fs capability set has landed upstream and is available in NVX prerelease v0.1.0-dev.be859aa77ffa.

The prototype served as the reproduction and upstream-development vehicle for sandbox mounting and guest-caller ownership. Its local patches are no longer an appropriate implementation or validation source for AWF.

Work

• Remove .github/workflows/nvx-virtfs-repro.yml.
• Remove scripts/nvx-virtfs-repro/, including:
  • apply-patch.py;
  • build-patched-initramfs.sh;
  • openvmm-mount-owner.patch; and
  • repro.sh.
• Remove or update references to the prototype, Sandbox mode never mounts the live virtio-fs share (--mount) inside the workload container microsoft/nvx#216, and locally carried OpenVMM patches.
• Confirm no active runtime, release, documentation, or validation path depends on these files.

Rationale

Upstream NVX now contains the required live-share functionality:

• Mount live virtio-fs shares inside the sandbox container microsoft/nvx#294 — mount live virtio-fs shares inside sandbox mode;
• sandbox: support symlink creation in rw virtio-fs workspace shares microsoft/nvx#302 — symlink support in read-write shares;
• sandbox: map virtio-fs share ownership to the caller with root squash microsoft/nvx#391 — caller ownership and root squash;
• sandbox: attach multiple virtio-fs shares with independent ro/rw modes microsoft/nvx#401 — multiple shares with independent read/write modes; and
• sandbox: add --mount-write and --mount-allow to live virtio-fs shares microsoft/nvx#413 — write narrowing and readable exemptions beneath denied paths.

The merged workflow was explicitly labeled throwaway and only triggers on the old nvx-virtfs-repro branch. Keeping the patches would create a misleading duplicate implementation and increase maintenance and security-review burden.

Acceptance criteria

• All files added by NVX: live virtio-fs workspace share + guest-caller ownership (prototype for microsoft/nvx#216) #9027 are removed or replaced by production-facing references.
• No repository code, workflow, or documentation references the removed prototype paths.
• Repository lint, type checking, build, and relevant workflow validation pass.
• The issue/PR description points to the upstream NVX release as the supported source of these capabilities.

Dependencies

None. This cleanup can run in parallel with validating the new NVX release.