dsh-long-term-memory: Deterministic Hierarchical Long-Term Memory for DeepSeek Harness

`dsh-long-term-memory` is a persistent memory plugin for DeepSeek Harness (DSH). It uses JSONL files and a CJK-aware BM25 algorithm to provide agents with deterministic, hierarchical (user/global/workspace) long-term memory. The plugin supports automatic summary injection, security threat scanning, and data correction, without requiring an external vector database or additional model calls, and enables memory writing, retrieval, and management through tools and slash commands.