Add HELLRAISERS Zombie Plague server

[KULTHX]

Summary

• Add HELLRAISERS | ZOMBIE PLAGUE to the Counter-Strike (cstrike) list in servers/cstrike.toml.
• Declare GoldSrc protocol 48 and provide the operator contact.

Validation

• ./tests/run.sh: 52 tests passed.
• Project validator: ready to merge; the server responded on protocol 48 and reported gamedir cstrike.

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[github-actions]

Server list PR validation

✅ Ready to merge — 1 entry verified, no problems found.

Probed 1 new or changed entry.

Gamedir	Address	Change	Claimed	Responder	Host	Notes
cstrike	16.170.223.249:27015	new	48 (GoldSrc)	48 (GoldSrc)	HELLRAISERS | ZOMBIE PLAGUE	✅ answered on the declared protocol.

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_{Probes can be flaky on the first try; the nightly publish workflow re-probes with a 48 h grace window, so a single ❌ here is not necessarily fatal. Re-push to re-run.}