Register Capsule CRM contacts for a webinar without duplicates

**Objective:** Register the Capsule CRM contacts described by `{contacts}` for the upcoming GoTo webinar `{webinar}`, skipping anyone already registered. Confirm before writing.

**Step 1: Find the webinar on GoTo Webinar**

Call `goto-webinar-get-webinar` with `webinar-name.contains` set to `{webinar}` (or `webinar-key` if it is a numeric key) and `date.from` set to today. If more than one upcoming webinar matches, list each with its name, date and webinar key and stop. If none matches, say so and stop. Keep its `webinar-key`.

**Step 2: Get the organizer key**

`goto-webinar-add-registrant` needs an `organizer-key`, and no GoTo Webinar tool returns one. Use `{organizer-key}` if given. If it is blank, ask the user for the organizer key of this webinar's organizer and stop until they give it.

**Step 3: Find the contacts in Capsule CRM**

`{contacts}` describes who to invite: an owner name, an organization name, a city, state or country, or a comma-separated list of emails. Turn it into filters on `capsule-crm-get-party` (`owner-name`, `organization-name.contains`, `city`, `state`, `country`, or `email` once per address), with `type` set to a person. If the description does not map onto these filters, say which filters exist and stop. Keep people with an email and a first and last name; list the rest as skipped. If more than 50 people match, stop and ask the user to narrow the list.

**Step 4: Skip anyone already registered**

For each email, call `goto-webinar-get-registrant` with `webinar-key` and `email`. Skip anyone who already has a registration.

**Step 5: Confirm the plan**

Show the webinar name and date, then a table: name, email, organization, Capsule owner. Show the skipped people separately with the reason. Show the plan as a table and ask the user to confirm. Do not write anything until they say yes. If they remove rows, drop those rows.

**Step 6: Write and report**

For each confirmed row, call `goto-webinar-add-registrant` once with `webinar-key`, `organizer-key`, `first-name`, `last-name`, `email`, and `organization` and `job-title` from Capsule where present. Then report: people registered, people already registered, people skipped and why, and any write that failed with its error.

**Rules & Guidelines:**

* `capsule-crm-*` tools are on the capsule-crm server; `goto-webinar-*` tools are on the goto-webinar server. If either set is missing, say which server is not connected and stop.
* The only write tool this prompt may call is `goto-webinar-add-registrant`, once per confirmed person. Do NOT call `goto-webinar-delete-registrant`, `capsule-crm-add-note`, `capsule-crm-add-task` or `capsule-crm-update-party`.
* Never register someone for a webinar that has already happened.

**Validation:**

* Capsule stores a person's name as one `name`; split it into first and last name at the last space, and say so in the plan for any name that does not split cleanly.
* If the organizer key is rejected, stop after the first failure and ask the user to check it rather than repeating the error for every person.
* If other writes fail, carry on with the rest and report the failures at the end.