`registry__initialise`

Start a work session before calling other Registry tools. The session record lets a reviewer read related calls as one piece of work.

Inputs: optional objective, client, client_version, and protocol_version. These fields are recorded as supplied and do not affect authorization.
Returns: an mcp_session_id and the created session record.
Effect: writes an mcp_session artifact in the account’s shared root.

Pass the returned mcp_session_id on later tool calls. The field is optional, so a failed or unavailable initialisation does not block other tools.