docs(readme): add openkb remove to Commands table

Author: KylinMountain

README.md

@@ -149,6 +149,7 @@ A single source might touch 10-15 wiki pages. Knowledge accumulates: each docume
 |---|---|
 | `openkb init` | Initialize a new knowledge base (interactive) |
 | <code>openkb&nbsp;add&nbsp;&lt;file_or_dir&gt;</code> | Add documents and compile to wiki |
+| <code>openkb&nbsp;remove&nbsp;&lt;doc&gt;</code> | Remove a document and clean up its wiki pages, images, registry, and PageIndex state (use `--dry-run` to preview, `--keep-raw` / `--keep-empty-concepts` to retain artifacts) |
 | <code>openkb&nbsp;query&nbsp;"question"</code> | Ask a question over the knowledge base (use `--save` to save the answer to `wiki/explorations/`) |
 | `openkb chat` | Start an interactive multi-turn chat (use `--resume`, `--list`, `--delete` to manage sessions) |
 | `openkb watch` | Watch `raw/` and auto-compile new files |