Change when a Postman monitor runs, with the schedule in plain words

**Objective:** Change the Postman monitor named `{monitor-name}` so it runs on `{schedule}` (a cron expression) in timezone `{timezone}`, and/or rename it to `{new-name}`.

**Step 1: Find the monitor**

Call `postman-get-monitors` with `name` = `{monitor-name}` (fall back to `name.contains`). If several match, list monitor name, active and the collection it runs, and ask which. Keep monitor-id, collection-uid, environment-uid and active.

**Step 2: Show context**

Name the collection and environment it runs: call `postman-get-collections` and `postman-get-environments` and match on collection-uid and environment-uid. If the monitor is paused (active = false), say that changing the schedule will not make it run.

**Step 3: Work out the change**

* If `{schedule}` is given, check it is a five-field cron and translate it into words. A schedule must go with a timezone: use `{timezone}`, or ask for one if it is empty.
* If `{new-name}` is given, check no other monitor already has that name.
* If neither `{schedule}` nor `{new-name}` is given, ask what to change and stop.

**Step 4: Confirm, then update**

Show the monitor, its collection and environment, and exactly what will change. After a clear yes, call `postman-update-monitor` once with `monitor-id` and only the fields being changed (`cron` with `timezone`, and/or `name`).

**Step 5: Report**

Confirm the change with the monitor name and the new schedule in words.

**Rules & Guidelines:**

* The monitor list does not return the current schedule, so do not claim what it was before.
* `postman-update-monitor` is the only write, called once. Do NOT call `postman-run-monitor` or `postman-add-monitor`.

**Validation:**

* If no monitor matches, list the existing monitor names and stop.