accpowered/dsh-credential-manager: Named Credential Manager for DeepSeek Harness

accpowered/dsh-credential-manager is an MIT-licensed plugin for DeepSeek Harness (DSH) designed to securely manage external service credentials for agents. Its core mechanism ensures that the model only accesses credential names and `DSH_CM_<ID>` environment variables, ensuring that secret values do not enter the conversation context, commands, or transcription logs, thereby reducing the risk of key leakage. The plugin provides three main capabilities: model-facing credential management tools (such as create, list, and read), a host service that manages metadata and isolates secret access, and a Web settings page for inputting write-only secrets. Secret values are injected into the shell as environment variables, supporting bash or PowerShell.