dsh--validate: JSON Validation and Repair

The dsh--validate plugin is a one-stop solution implemented in pure Node.js that addresses the cumbersome aspects of handling JSON data in DSH environments. It offers two core capabilities, “validation and error location” and “automatic repair,” by automatically detecting and fixing syntax errors (such as comments, trailing commas, and single quotes) and directly reporting the line and column numbers of errors. Once installed, it can be quickly invoked through the `validate_json` and `fix_json` tools. The source code should be reviewed before use to ensure security and compliance.