@sandersyao/dsh-storage-mysql: MySQL Storage Backend for DeepSeek Harness

`sandersyao/dsh-storage-mysql` is a storage plugin for DeepSeek Harness (DSH), intended to replace the default JSON file storage. It registers a MySQL backend that persists key-value storage in InnoDB tables, providing ACID transactions, crash recovery, and multi-process sharing capabilities. The plugin supports automatic schema migration (three tables: units, records, and meta) and prevents SQL injection through parameter binding. After installation, configure environment variables for the database connection and set `storage-domain.backend` to `mysql` in your code to enable its use in distributed deployments.