Method createMultiProject

src/node/services/workspaceService.ts:3335–3719

* Scope note: unlike create(), this does not accept creation-time `tags` — * multi-project workspaces currently can't be tagged atomically (callers * would need a follow-up updateTags, reintroducing a crash-window gap). * Thread tags through here if orchestration loops ever target multi-pro

(
    projects: ProjectRef[],
    branchName: string,
    trunkBranch: string | undefined,
    title?: string,
    runtimeConfig?: RuntimeConfig
  )

   * workspaces.
   */
  async createMultiProject(
    projects: ProjectRef[],
    branchName: string,
    trunkBranch: string | undefined,
    title?: string,
    runtimeConfig?: RuntimeConfig
  ): Promise<Result<FrontendWorkspaceMetadata>> {
    assert(projects.length > 1, "createMultiProject requires at least two projects");
    if (!this.isMultiProjectWorkspacesExperimentEnabled()) {
      return Err(MULTI_PROJECT_WORKSPACES_DISABLED_ERROR);
    }

    let initLogger: ReturnType<WorkspaceService["createInitLogger"]> | null = null;

    try {
      const validation = validateWorkspaceName(branchName);
      if (!validation.valid) {
        return Err(validation.error ?? "Invalid workspace name");
      }

      const normalizedProjects = projects.map((project) => ({
        projectPath: stripTrailingSlashes(project.projectPath),
        projectName: project.projectName,
      }));
      const primaryProject = normalizedProjects[0];
      assert(primaryProject, "createMultiProject requires a primary project");

      const configSnapshot = this.config.loadConfigOrDefault();
      for (const project of normalizedProjects) {
        const projectConfig = configSnapshot.projects.get(
          stripTrailingSlashes(project.projectPath)
        );
        if (projectConfig?.parentProjectPath) {
          return Err(
            `Sub-project ${project.projectName} cannot be added directly to a multi-project workspace. Add its parent project instead.`
          );
        }
      }

      for (const project of normalizedProjects) {
        const projectConfig = configSnapshot.projects.get(
          stripTrailingSlashes(project.projectPath)
        );
        if (!projectConfig?.trusted) {
          return Err(
            `Project ${project.projectName} must be trusted before creating workspaces. Trust the project in Settings → Security, or create a workspace from the project page.`
          );
        }
      }

      const workspaceId = this.config.generateStableId();

      let finalRuntimeConfig: RuntimeConfig = runtimeConfig ?? {
        type: "worktree",
        srcBaseDir: this.config.srcDir,
      };

      if (this.policyService?.isEnforced()) {