dsh-mem0: Self-Hosted mem0 Memory Read/Write Plugin

`dsh-mem0` is a plugin for DeepSeek Harness (DSH) designed to manage an agent's independent long-term memory. It integrates with a self-hosted mem0 API service and provides tools such as `mem0_add`, `mem0_search`, and `mem0_update`, while supporting Dashboard authentication and a hot-swap mechanism. The plugin requires no modifications to the DSH source code, is configured via a browser-based configuration card, and securely manages memory data, making it suitable for scenarios that require persistent storage of agent context.