Set up new Zendesk customer organizations in one pass

**Objective:** Make sure organization `{organization-name}` exists in Zendesk and that each person in `{user-emails}` (comma separated) is a user and a member of it.

**Step 1: The organization**

Call `zendesk-get-organization` with name `{organization-name}`. If it exists, keep its organization-id. If several match, list them and stop. If none match, plan to create it.

**Step 2: The people**

Split `{user-emails}` on commas and trim each. For each email, call `zendesk-get-user` with email set to it.

* Found: keep user-id, name, role and organization-name.
* Not found: plan to create them as role end-user, with name taken from the part before @ unless the user gives one.

**Step 3: Existing memberships**

If the organization exists, call `zendesk-get-organization-member` with its organization-id and note which user-id values are already members.

**Step 4: Confirm the plan**

Show one list: the organization (exists or create), each person (exists or create) and each membership (exists or add). Flag any found user whose role is agent or admin; they are staff, and adding them to a customer organization is usually a mistake. Wait for an explicit yes, and let the user drop items.

**Step 5: Apply, in this order**

1. If needed, call `zendesk-add-organization` once with name `{organization-name}` and keep the returned id.
2. For each person to create, call `zendesk-add-user` once with name, email, role end-user and organization-id.
3. For each existing user who is not yet a member, call `zendesk-add-organization-member` once with organization-id and user-id. Skip users just created in step 2; they already belong.

Stop at the first failure and report what was done and what was not.

**Step 6: Verify**

Call `zendesk-get-organization-member` with the organization-id and report the final member list.

**Rules & Guidelines:**

* Only call `zendesk-add-organization`, `zendesk-add-user` and `zendesk-add-organization-member`, only for items the user confirmed, and never twice for the same item.
* Do NOT call `zendesk-update-user` or `zendesk-update-organization`; this prompt adds, it does not change existing records.
* Do not move a user out of another organization.

**Validation:**

* If `{user-emails}` is blank, set up the organization only.
* Skip, and report, any entry that is not a valid email address.