dsh-balance-local: DeepSeek Harness Balance Inquiry Plugin

`dsh-balance-local` is a DeepSeek Harness plugin designed to monitor API balances locally. It integrates queries into the DSH interface, providing an intuitive settings panel and input-field badges, with automatic refresh enabled by default every 60 seconds. Its core value lies in security: the API key is parsed only by the Host process, data is masked before being returned, and remote access is prohibited by default. Installation requires building from source and configuring Cordis. After installation, it automatically reuses keys from the `dsh` credential store, requiring no additional configuration.