Add CSOMOD server

[thepenguinguy2]

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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	81.181.244.5:27015	new	48 (GoldSrc)	48 (GoldSrc)	[ZOMBIES]+[CSO MOD] [#1] CSOMOD.COM [since 2012]	✅ answered on the declared protocol.

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