servers: valve: change protocol

[Elinsrc]

No description provided.

[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
valve	2.26.26.83:27015	protocol 49 → 48	48 (GoldSrc)	48 (GoldSrc)	ReHLDS Updated DM	✅ 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.}