@beihzb

Per-conversation x-opencode-session injection for OpenCode Go in DeepSeek Harness - fixes 400 MissingSessionID without breaking other providers

Per-session environment selector for DeepSeek Harness: Python / R / CLI slots from conda, standalone R, WSL, or custom paths, via /env, session_env, DSH_ENV_* facts, and a header dropdown.

Native Jupyter-style notebook for DeepSeek Harness: real ipykernel sidecar + VS Code-aligned cell UI, tqdm progress, inline figures, per-cell AI revision.