dsh-emergency-fund: Emergency Fund Planning Plugin

The `dsh-emergency-fund` plugin for DeepSeek Harness (DSH) is a financial planning tool implemented purely in Node.js. It enables developers to integrate domain-specific emergency fund planning into their agents without any network dependency. The plugin accepts parameters as input and directly generates a household financial planning plan. Developers must install and enable the plugin, then invoke the `emergency_fund` tool to use it. It depends on `@deepseek-ai/cordis` ^4.0.1 and `@deepseek-ai/dsh-tools` >=0.1.0-rc.6.