dsh-plugin-academic-writing: DeepSeek Harness Academic Writing Toolkit

The `dsh-plugin-academic-writing` plugin for DeepSeek Harness (DSH) is designed to address structural gaps and non-standard formatting in academic writing produced by agents. By encapsulating ten core tools, including outline generation, heading variants, citation formatting, and language style validation, it provides support for structural planning, compliance checking, and LaTeX code generation in paper writing. The plugin adopts a pure-logic design with no file system access. Compatibility issues have been fixed, and it can be installed via the CLI and integrated into DSH workflows.