dsh-trivium: In-process graph memory plugin for DeepSeek Harness

dsh-trivium is a process-in-memory graph memory plugin for DeepSeek Harness (DSH) based on TriviumDB, designed to solve the issue of agent memory not persisting across sessions, eliminating the need for external vector databases or independent services. It structures memory into four tools—ctx_find, ctx_read, ctx_remember, and ctx_link—with nodes categorized into Entities, Preferences, Decisions, and Experiences, while edges record associations. By default, the plugin operates quietly, injecting a compact graph of approximately 400 tokens into new sessions only once and querying the rest on demand. It supports manual editing for correction, strict write hygiene (filtering out garbage text and keys), optional embedding vector retrieval, and Git collaboration. It is installed via the `dsh plugin` command, utilizes one `.tdb` file per workspace, and fails without blocking.