dsh-dcp: DeepSeek Harness Deterministic Compression Backend

dsh-dcp is a deterministic context pruning and compression plugin for DeepSeek Harness (DSH). It does not use an LLM to summarize content; it only retains factual details from the conversation, such as commands, error messages, and original wording, ensuring stable output with zero additional token consumption. The plugin inherits DSH's security mechanisms, supports management via the `/dcp` command, and optimizes pricing for Chinese-language scenarios. It is easy to install and well suited for low-cost, stable management of Chinese conversational context.