DeepSeek Harness Offline Architecture Advisor Plugin

The `dsh-arch-advisor-offline` plugin for DeepSeek Harness (DSH) bundles the open-source knowledge base [awesome-architecture](https://github.com/study8677/awesome-architecture) into the plugin itself, achieving zero network access at runtime. It includes 7 tools (such as `arch_ask_offline`, `arch_design_offline`, and `arch_docs_offline`), supporting the entire workflow from knowledge retrieval and architecture design to documentation generation. The plugin depends on `@deepseek-ai/cordis` 4.0.1+ and is suitable for architecture consulting in offline or highly restricted network environments.