Cut and verify the v0.5.1 release

[itdevwu]

Outcome

v0.5.1 shipped the container-aware bounded Agent workflow and attestable GitHub-hosted release path. The release contains the Linux archive, SHA256 sidecar, and SPDX JSON SBOM, with build provenance and SBOM attestations bound to the archive.

Verified by

• PR Prepare v0.5.1 Agent and release usability #43 was rebased into master after all GitHub-hosted CI checks passed.
• Release workflow 33275553234 built CUDA 12 and CUDA 13 Agents and packaged the CLI on Ubuntu 22.04.
• The workflow and an independent local run downloaded the public archive and verified its checksum, SPDX structure, provenance and SBOM attestations, installation, and removal.
• The CLI and both shipped Agent ELFs require at most GLIBC_2.34 and expose the expected CUDA 12 and CUDA 13 linkage.
• Hardware collector behavior and ABI were unchanged; the existing local maintainer hardware suite remains the recorded evidence.

[itdevwu]

Released and independently verified as v0.5.1: https://github.com/itdevwu/xprobe/releases/tag/v0.5.1