ClassifyTargets kept a name every time it appeared in DNSWATCHER_TARGETS,
so example.com,Example.com. put example.com in the domain list twice and
every check looked it up, checked its ports and its certificates twice,
sending two expiry warnings per TLS check. It now skips a name it has
already kept, comparing after the lower-casing and trailing-dot removal
it already did; the list keeps the order of first appearance.
Model: opus-5-5
Replace DNSWATCHER_DOMAINS and DNSWATCHER_HOSTNAMES with a single
DNSWATCHER_TARGETS env var. Names are automatically classified as apex
domains or hostnames using the Public Suffix List
(golang.org/x/net/publicsuffix).
- ClassifyDNSName() uses EffectiveTLDPlusOne to determine type
- Public suffixes themselves (e.g. co.uk) are rejected with an error
- Old DOMAINS/HOSTNAMES vars removed entirely (pre-1.0, no compat needed)
- README updated with pre-1.0 warning
Closes#10