docs: explain Windows Docker daemon proxy setting (#25804)

## Summary
- document what **Use proxy for Windows Docker daemon** does on the
Docker Desktop settings page
- link the existing Registry Access Management and Settings Management
docs that already describe the related behavior

Fixes #25622

## Validation
- `git diff --check`
- `npx --yes markdownlint-cli2
content/manuals/desktop/settings-and-maintenance/settings.md`

---------

Co-authored-by: Niels Kaspers <nielskaspers@users.noreply.github.com>
Co-authored-by: Allie Sadler <102604716+aevesdocker@users.noreply.github.com>

Author: nielskaspers

content/manuals/desktop/settings-and-maintenance/settings.md

@@ -150,6 +150,16 @@ Used for `docker image pull` (always enforced - all `docker pull` and Compose pu
 >
 > The HTTPS proxy used for image scanning is configured using the `HTTPS_PROXY` environment variable.
 
+#### Windows Docker daemon proxy
+
+When you run Windows containers, enable **Use proxy for Windows Docker daemon**
+to let the Windows Docker daemon connect to Docker Desktop's internal proxy.
+This allows Windows containers to use the configured Docker Desktop proxy, and
+it is required if you want [Registry Access Management](/manuals/enterprise/security/hardened-desktop/registry-access-management.md)
+restrictions to apply to Windows image operations. Administrators can manage
+the same behavior with
+[**Override Windows "dockerd" port**](/manuals/enterprise/security/hardened-desktop/settings-management/settings-reference.md#override-windows-dockerd-port).
+
 #### Proxy authentication
 
 | Method |  Behavior | Notes |