Method registerSession

src/node/services/workspaceService.ts:2807–2817

* Register an externally-created AgentSession so that WorkspaceService * operations (sendMessage, resumeStream, remove, etc.) reuse it instead of * creating a duplicate. Used by `mux run` CLI to keep a single session * instance for the parent workspace.

(workspaceId: string, session: AgentSession)

   * instance for the parent workspace.
   */
  public registerSession(workspaceId: string, session: AgentSession): void {
    workspaceId = workspaceId.trim();
    assert(workspaceId.length > 0, "workspaceId must not be empty");
    assert(!this.sessions.has(workspaceId), `session already registered for ${workspaceId}`);
    if (this.transientStartupRecoverySessions.get(workspaceId) === session) {
      this.transientStartupRecoverySessions.delete(workspaceId);
    }

    this.sessions.set(workspaceId, session);
    this.attachSessionSubscriptions(workspaceId, session);
  }

  public emitChatEvent(workspaceId: string, message: WorkspaceChatMessage): void {
    const trimmed = workspaceId.trim();