DeepSeek Harness SQLite Data Tools Plugin

`dsh-tool-sqlite` is a zero-dependency plugin for DeepSeek Harness (DSH) designed to handle local `.db` files. Leveraging built-in Node.js modules, it provides core features such as listing files, inspecting table structures, and executing read-only SQL queries. To ensure security, the plugin enforces strict restrictions: only read-only operations are allowed, SQL statements are whitelisted, and path boundaries and output row counts are limited. Developers can easily enable it in DSH configuration to explore database data directly within the workspace.