dsh-compat-guardian: DeepSeek Harness Plugin Compatibility Check and Isolation Tool

`dsh-compat-guardian` is a plugin compatibility detection and isolation tool designed specifically for DeepSeek Harness (DSH). Through a sidebar UI and a standalone CLI, it provides environment checks, declarative conflict detection, runtime monitoring, and automatic isolation/recovery. When DSH fails to start, developers can use this tool to identify conflicting plugins, review history, and perform offline repairs, effectively reducing the risk of host crashes caused by configuration errors.