Assign Zendesk tickets and reply in one confirmed step

**Objective:** Assign Zendesk ticket `{ticket-id}` to agent `{assignee}` (a name or email), optionally set status `{new-status}` (default leave unchanged), and post the reply `{reply}` if one is given.

**Step 1: Load the ticket**

Call `zendesk-get-ticket` with ticket-id `{ticket-id}`. If nothing comes back, say so and stop. If status is closed, stop: closed tickets cannot be changed.

**Step 2: Resolve the agent to an id**

`zendesk-update-ticket` needs an assignee-id, and the ticket only carries a name, so look the agent up:

* If `{assignee}` contains @, call `zendesk-get-user` with email set to it.
* Otherwise call `zendesk-get-user` with name set to it; if that returns nothing, retry with name.contains.

Keep only users whose role is agent or admin and whose active is true. If none remain, stop and say why. If several remain, list them with email and stop.

**Step 3: Check the group**

Call `zendesk-get-group-member` with user-id set to the agent's user-id. If the ticket's current group-name is one of the agent's groups, keep it. Otherwise pick the agent's default-group, call `zendesk-get-group` with that group-name to get its group-id, and plan to move the ticket there, because Zendesk rejects an assignee who is not in the ticket's group.

**Step 4: Confirm**

Show the user: ticket-id, subject, current and new assignee, current and new group, current and new status, and the exact reply text (public). Ask for confirmation and wait. Do not continue without an explicit yes.

**Step 5: Update once**

Call `zendesk-update-ticket` exactly once with id `{ticket-id}`, assignee-id, group-id if it changes, status if `{new-status}` is given, and, if `{reply}` is given, comment set to it with comment-public true.

**Step 6: Confirm the result**

Call `zendesk-get-ticket` with ticket-id `{ticket-id}` and report the stored assignee-name, group-name and status. If a reply was sent, call `zendesk-get-ticket-comment` with ticket-id `{ticket-id}` and show the newest comment.

**Rules & Guidelines:**

* The only write allowed is one call to `zendesk-update-ticket`, after the user confirms. Do NOT call `zendesk-add-ticket-comment` separately; the reply goes in the same update.
* Do NOT call `zendesk-add-group-member` to make an agent fit a group.
* Never change priority, type, subject or tags in this prompt.

**Validation:**

* If the update fails, report the error and do not retry automatically.
* If `{new-status}` is not one of new, open, pending, hold or solved, stop and ask.