DeepSeek Harness In-Place Message Editing Plugin: dsh-message-rewrite

The `dsh-message-rewrite` plugin introduces a Codex-like message editing mechanism to DeepSeek Harness (DSH). It allows users to directly modify historical user messages within a session; older assistant responses and any subsequent content are truncated and regenerated, preserving conversational coherence. The plugin supports in-place message editing, a refined overlay, edit chains, automatic forking of intermediate messages, and virtual scrolling compatibility. It must be installed via a profile bundle, and users should be aware of potential configuration file conflicts. This plugin aims to improve the experience of AI debugging and conversation correction.