flowctx-dsh: Local First Context Engine for DeepSeek Harness

flowctx-dsh is a local-first context management plugin for DeepSeek Harness (DSH) designed to address context blurring, information loss, and repetitive search issues caused by long sessions in agent programming. As an additive extension of `dsh-compaction-basic`, it introduces an engineering memory model, with core capabilities including: 1. **Engineer Handover Note Summaries**: Enabled by default, converts summaries into structured handover notes containing failure paths and key identifiers, surpassing general narrative summaries. 2. **Hierarchical DAG Summaries**: Enabled by default, collapses history into hierarchical summary nodes to prevent information generalization in long sessions. 3. **Reversible Tool Result Projection**: Enabled by default, structurally compresses tool results exceeding a threshold and stores the original hash, supporting on-demand retrieval of the original content. 4