docs(README): add documentation for custom SSL certificate and key options in configuration

README.md

@@ -203,6 +203,7 @@ MeshChatX supports both CLI args and env vars.
 | `--host`        | `MESHCHAT_HOST`        | `127.0.0.1`  | Web server bind address                                                      |
 | `--port`        | `MESHCHAT_PORT`        | `8000`       | Web server port                                                              |
 | `--no-https`    | `MESHCHAT_NO_HTTPS`    | `false`      | Disable HTTPS                                                                |
+| `--ssl-cert` / `--ssl-key` | `MESHCHAT_SSL_CERT` / `MESHCHAT_SSL_KEY` | (none) | PEM certificate and private key paths; both must be set together. Overrides auto-generated certs under the identity `ssl/` directory. |
 | `--headless`    | `MESHCHAT_HEADLESS`    | `false`      | Do not auto-launch browser                                                   |
 | `--auth`        | `MESHCHAT_AUTH`        | `false`      | Enable basic auth                                                            |
 | `--storage-dir` | `MESHCHAT_STORAGE_DIR` | `./storage`  | Data directory                                                               |