dsh-policy-drift-proof: Policy Drift Evidence for DeepSeek Harness

`dsh-policy-drift-proof` is a DeepSeek Harness plugin maintained by dongsheng123132, designed to generate read-only, content-addressed evidence of policy or configuration drift. The tool pins baselines and observed snapshots through SHA-256 hashing and revision pinning, supporting the `ordered-not-weaker`, `set-no-additions`, and `exact` rules. Uncovered changes are flagged as `UNCLASSIFIED_DRIFT` and result in failure, ensuring the auditability of evidence. Core functionality includes outputting JSON objects via the CLI's `inspect` and `verify` commands, where the `verify` command operates within a specified directory.