dsh-validate: Offline Validation and Chinese Amount/Tax Calculation Plugin

`dsh-validate` is a configuration-layer plugin for DeepSeek Harness (DSH), focused on offline deterministic algorithmic validation and arithmetic calculations based on ISO/GB standards. It provides 18 tools, such as those for national ID cards, bank cards, and license plates, and supports features such as converting monetary amounts into Chinese uppercase financial numerals, calculating Chinese individual income tax, and estimating loans. It does not rely on external APIs and processes data in memory, ensuring security and a low cost ($0.001 per invocation). This makes it suitable for replacing unstable API calls while ensuring the accuracy of financial and qualification validations.