dsh-debt-plan: Debt Management: Return Household Financial Planning Plan by Parameters

The `dsh-debt-plan` plugin for DeepSeek Harness (DSH) is a local debt management tool implemented purely in Node.js. It runs offline, registers the `debt_plan` tool in the DSH process, and generates household financial planning plans based on provided parameters. Users only need to run an installation command to use it, making it suitable for privacy-sensitive or offline environments. The plugin is licensed under the MIT License.