docs(whp): rework DNS page for new Domains & DNS UI

The WHP DNS area was reworked from the old Domains page (left-side add
form + right-side DNS Management dropdown) into a searchable Domains &
DNS list plus a dedicated per-domain DNS records editor.

- Recapture whp-domains.png against the new list layout
- Add screenshots for the Add Domain modal, records editor, inline
  Add Record row, and bulk-action toolbar
- Add capture-dns.ts (fleet-redacted, viewport-only) following the
  existing capture-admin.ts pattern
- Rewrite add-a-domain.mdx Add Domain steps for the modal flow and
  point at the new records editor
- Add manage-dns-records.mdx how-to (add/edit/delete, type filter,
  bulk actions, verification, troubleshooting); renumber sidebar order

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/content/docs/whp/how-to/add-a-domain.mdx

@@ -27,24 +27,25 @@ import Support from '~/content/partials/support-link.mdx';
 
 <Steps>
 
-1. In the sidebar, click **Domains**.
-   ![WHP Domains page](~/assets/screenshots/whp/whp-domains.png)
+1. In the sidebar, click **Domains & DNS**. You'll see a searchable list of the domains on your account.
+   ![WHP Domains & DNS page](~/assets/screenshots/whp/whp-domains.png)
 
-2. Under **Add New Domain** on the left, type your domain (for example, `example.com`). Don't include `http://` or `www.` — just the bare domain.
+2. Click **Add Domain** in the top right. In the dialog, type your domain (for example, `example.com`) — just the bare domain, with no `http://` or `www.`
+   ![Add Domain dialog](~/assets/screenshots/whp/whp-dns-add-domain.png)
 
-3. Click **Add Domain**.
+3. Click **Add Domain** to confirm. The domain appears in the list with a green **Active** status.
 
 </Steps>
 
-WHP creates the standard set of DNS records automatically for the new domain:
+WHP creates a DNS zone with the standard set of records automatically for the new domain:
 
 - **A record** for the apex domain → your server's IP
 - **CNAME** for `www` → the apex
 - **NS records** for the nameservers
 - **MX record** → the mail server
-- **TXT record** for SPF
+- **TXT records** for SPF and DKIM
 
-You can review and tweak any of these from the **DNS Management** panel on the right side of the Domains page (select the domain from the dropdown).
+You can review and tweak any of these — click **Manage DNS** next to the domain to open the records editor. See [Manage DNS records](/whp/how-to/manage-dns-records/) for the full walkthrough.
 
 ## Point your DNS at us
 
@@ -54,7 +55,7 @@ There are two paths depending on where the domain is registered:
 
 **Registered elsewhere.** At your registrar, do one of the following:
 
-- Set the **nameservers** to the values shown on the Domains page (recommended — gives us full DNS control, easier to support), **or**
+- Set the **nameservers** to the values shown in **Manage DNS** (the **NS** records) — recommended, as it gives us full DNS control and is easier to support — **or**
 - Keep your existing nameservers and add an **A record** pointing the domain to the IP shown on the **Dashboard** page under Server Information.
 
 ## Verify it worked
@@ -76,6 +77,7 @@ Once DNS resolves, visiting your domain in a browser will reach WHP — though y
 
 ## Related
 
+- [Manage DNS records](/whp/how-to/manage-dns-records/)
 - [Create a site](/whp/how-to/create-a-site/)
 
 ## Still stuck?