dsh-multi-candidate: DeepSeek Harness Multi-Candidate Mode Plugin

The `dsh-multi-candidate` plugin of DeepSeek Harness (DSH) improves the success rate and stability of complex tasks through a parallel generation and validation mechanism. It supports a freely draggable whale-panel interface, configuration-driven behavior, and session isolation. Users can configure options such as the number of candidates and secondary review, and once enabled via the Web GUI, the system automatically performs multi-candidate generation, validation, and best-candidate selection. Installing the required peer package and running the command activates the plugin; note that source code changes require reinstallation, and hot reload is supported only for client-side changes.