Take passwords and card numbers off Zendesk threads

**Objective:** On Zendesk ticket `{ticket-id}`, find the public comments that contain `{search-text}` (or, if blank, anything that looks like a password, card number, bank detail or API key) and make them private.

**Step 1: Read the public comments**

Call `zendesk-get-ticket-comment` with ticket-id `{ticket-id}`, public true and max-records 200. If nothing comes back, say there are no public comments and stop.

**Step 2: Find the matches**

* If `{search-text}` is given, match comments whose comment text contains it, ignoring case.
* If it is blank, look for credential-like content: long digit runs that look like card numbers, IBAN or account numbers, words like password or secret followed by a value, and long random tokens.

For each match, keep comment-id, created-date, author-id and a masked excerpt (show only the first and last two characters of the sensitive value).

**Step 3: Confirm**

List the matches with their masked excerpts and ask which to make private. Wait for an explicit yes, per comment or for all.

**Step 4: Make private**

For each confirmed comment, call `zendesk-make-ticket-comment-private` once with ticket-id `{ticket-id}` and id set to the comment-id.

**Step 5: Verify and advise**

Call `zendesk-get-ticket-comment` with ticket-id `{ticket-id}` and public true again and confirm none of the chosen comment-id values remain. Remind the user that making a comment private does not delete it or recall emails already sent, and that exposed credentials should be rotated.

**Rules & Guidelines:**

* The only write allowed is `zendesk-make-ticket-comment-private`, once per confirmed comment.
* Never echo the full sensitive value in the conversation.
* Do NOT call `zendesk-add-ticket-comment` or `zendesk-update-ticket` to explain the change to the requester unless the user asks separately.

**Validation:**

* If nothing matches, say so and do not change anything.
* If the ticket cannot be found, say so and stop.