Fixes#385
Updates DNS authentication documentation to correctly specify that TXT
records should be placed at the root domain (e.g., `example.com`) rather
than the `_mcp-registry` subdomain.
The implementation correctly looks up TXT records at the root domain,
but the documentation incorrectly instructed users to create records at
`_mcp-registry.<domain>`. This mismatch was causing authentication
failures.
## Why use root domain instead of subdomain?
The root domain approach is clearer: if you want to publish to
`com.example/my-server`, you authenticate with `example.com`, not
`_mcp-registry.example.com`.
It also aligns with other TXT DNS standards, e.g. SPF. (That said, there
are other DNS standards that use subdomains e.g. DKIM 🤷)
## Changes
- Updated publish-server.md to remove `_mcp-registry.` prefix from DNS
examples
- Updated CLI commands reference documentation
- Updated namespacing explanation documentation
d43d0bfeef