When a wildcard cert (e.g. *.domain.de) existed and a proxy host was created
for a subdomain (e.g. sub.domain.de) without explicitly linking it, the
certificates page showed it as a separate ACME entry. Now hosts covered by
an existing wildcard cert are attributed to that cert's "Used by" list instead.
Closes#110
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
