Add screenshots to the quarantine self-service article

Four screenshots of the actual PMG quarantine portal (login with
Request Quarantine Link, the request dialog, the held-mail list, and
the message-selected action toolbar), captured via a new
capture-quarantine.ts following the existing capture-*.ts pattern
(1440x900, deviceScaleFactor 2, viewport-only).

Redacted: real server hostname, the test mailbox address, and the
synthetic test-message content are all swapped for believable generic
customer-facing examples before each shot.

Restructured the article's two near-duplicate step lists ("Check your
quarantine" / "Get in without waiting") into one flow now that the
screenshots show it's genuinely a single screen, not two paths.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VXgBxaVABantBF8twz4LpU

tools/screenshots/README.md

@@ -63,6 +63,7 @@ npx tsx tools/screenshots/capture-dns.ts
 | `capture-site-builder.ts` | Site Builder editor states | `WHP_USER` |
 | `capture-dns.ts` | Domains & DNS list, Add Domain modal, records editor, bulk toolbar | `WHP_USER` |
 | `capture-email.ts` | Email page "Mail Client Setup" section (autodiscovery DNS records) | `WHP_USER` |
+| `capture-quarantine.ts` | PMG spam quarantine portal (login, request-link dialog, held-mail list, message actions) — **not a WHP page**, targets the mail filtering gateway directly | `PMG_BASE` + `PMG_TICKET_URL` (a real quarantine ticket link, e.g. from a test mailbox's "Request Quarantine Link" email) instead of WHP_USER/PASS |
 
 Each script carries its own `redact()` (text-node + input-value swaps) so fleet hostnames, IPs, and customer data become neutral placeholders while brand/demo domains stay visible. Copy the closest existing script when adding a new section — match its viewport (1440×900), `deviceScaleFactor: 2`, and **read-only** discipline (open modals and tick boxes for the shot, but never save/delete/submit).