dsh-dev-databases: Local Database Entry Query Plugin

`dsh-dev-databases` is a DeepSeek Harness (DSH) plugin maintained by uckkk for local management of structured data. Implemented purely in Node.js with no network dependencies, it provides two core features: listing entries and querying details. Developers only need to run the installation command to invoke the tools directly in a session. It is suitable for offline environments, requires the `@deepseek-ai/cordis` and `@deepseek-ai/dsh-tools` dependencies to be present, and source code security should be checked before installation.