dsh-update-copilot: DSH Update Assistant

dsh-update-copilot is an update assistance plugin for DeepSeek Harness (DSH), designed to safely manage updates for various dependency types. It performs a one-time scan of third-party plugins across DSH core, bundles, and individual profiles, covering npm, git commits, and local link sources. The plugin presents version distances, risk levels, and changelogs through semver analysis and applies specific comparison logic based on source types. Regarding execution, it enforces strict guardrails: npm/Git dependencies are handled exclusively via the official CLI, while link types invoke git updates in the local directory (including automatic stashing and manual conflict intervention). It mandates explicit confirmation, single-flight locking, and timeout protection, and explicitly disallows automatic upgrades to the DSH core.