dsh-token-saver: DeepSeek Harness Plugin

`dsh-token-saver` is a Cordis plugin designed for DeepSeek Harness, optimized to reduce token consumption in long-running tasks by mounting extension points. Core features include lossless head-and-tail trimming, grep result folding, automatic context compression, and optional LLM-based summarization. It offers conservative, balanced, and aggressive modes. Benchmarks show the balanced mode saves approximately 98.5% of tokens on average. Installation requires Node.js >= 22.19.0, configuration is flexible, and it is well suited to scenarios with large files and frequent retrieval results.