caddy: Dynamic DNS generates incorrect zone for non-wildcard subdomain domain entries

[0xMH]

Plugin name and version: os-caddy (current master)

Describe the bug

When a non-wildcard domain entry like blog.example.com has Dynamic DNS enabled, the Caddyfile template generates an incorrect dynamic_dns domains block:

dynamic_dns {
    domains {
        blog.example.com @
    }
}

The caddy-dynamicdns module treats the first field as the DNS zone name. Since blog.example.com is not a DNS zone (the zone is example.com), the DNS provider lookup fails silently and the record never gets updated.

The correct output should be:

dynamic_dns {
    domains {
        example.com blog
    }
}

Steps to reproduce

1. Create a domain entry with FromDomain set to blog.example.com (not a wildcard, not a bare domain)
2. Enable Dynamic DNS on this entry
3. Reconfigure Caddy
4. Check the generated Caddyfile - the dynamic_dns block will have blog.example.com @ instead of example.com blog

Root cause

In the Caddyfile template (line 155), the else branch for non-wildcard domain entries appends cleanedDomain + " @" without checking if the domain is a subdomain (has more than 2 parts). The subdomain loop (lines 161-164) already has the correct split logic but it only applies to entries created as subdomains under a wildcard parent.

Current workaround

Create a wildcard parent domain (*.example.com) and nest subdomains under it. This forces the subdomain template path which correctly splits the zone and record name.

[Monviech]

If its a subdomain, check the dynamic dns checkbox in the subdomain entry, not in the base domain entry.

https://docs.opnsense.org/manual/how-tos/caddy.html#dynamic-dns

It explains here which domain type produces which dyndns records.

So your current workaround is the intended configuration model, I dont want to fix anything there without necessity since its stable since years by now.