* fix(sub): append host serverDescription to hysteria links
A host's Description reached vless/trojan/ss through buildEndpointLinks, but
genHysteriaLink renders the fragment in its own externalProxy loop and never
added the suffix, so Happ fell back to its "Hysteria | hysteria | TLS" caption
for every Hysteria server on a host that also serves VLESS (#6738).
Reuse appendHappServerDescription with the description the endpoint map already
carries, so no key lookup is duplicated and a host with no description emits the
same bytes as before. genTuicLink (service.go:912) has the same gap; left alone
to keep this diff to the reported protocol.
Regression test is red without the fix for both hysteria:// and hysteria2://.
* chore(sub): trim the hysteria serverDescription regression test
The no-description test passed with and without the #6738 fix: the empty
description branch is already pinned by TestAppendHappServerDescription, so
it certified nothing about this change. Also cut the remaining test's comment
block to the two-line limit CLAUDE.md sets.
---------
Co-authored-by: MHSanaei <ho3ein.sanaei@gmail.com>