dsh-compat-guard: DeepSeek Harness Compatibility Governance Tool

`dsh-compat-guard` is a compatibility governance solution for DeepSeek Harness (DSH), designed to address plugin compatibility, storage changes, and data migration risks during version upgrades. The tool provides pre-upgrade checks (gates), machine-generated compatibility matrices, secure session data migration, and profile-level lock file management. By setting an alias to enforce `dsh-guard dsh`, users can automatically back up and validate the environment before performing operations, with support for snapshots, validation, and one-click rollback, providing defensive safeguards for data security in agent development environments.