dsh-session-export: Exporting DSH Sessions to Markdown and JSON

dsh-session-export is a DSH community plugin maintained by bwndlct, designed to export DeepSeek Harness (DSH) sessions into portable Markdown and structured JSON files for archival, reading, and downstream processing. The plugin is released under the MIT license and supports export triggering via the `session_export()` tool (available in all profiles) or the `/session-export` slash command (required in profiles that mount the commands service, such as web). Its core features include sequentially preserving user, assistant, and tool interactions, with robustness against unknown events, code fences, and oversized results (exceeding 8,000 characters will be truncated and marked).