Support for /select/tempo/api/mcp on vtselect

[lpetrazickisupgrade]

Is your feature request related to a problem? Please describe

When grafana-mcp connects to Grafana, it makes a /select/tempo/api/mcp request to every Tempo datasource. Since Victoria Traces suggests using a Tempo datasource for itself in Grafana, vtselect shows an error for every tenant we have and triggers a TooManyLogs alert.

{
  "ts": "2026-08-27T17:28:29.560Z",
  "level": "warn",
  "caller": "VictoriaMetrics@v1.149.1-0.20260811205936-d4a40004ef28/lib/httpserver/httpserver.go:396",
  "msg": "remoteAddr: \"[2600:1f14:b0d:fa02:2a87::5]:44468, X-Forwarded-For: 2600:1f14:b0d:fa01:1822::7, 2600:1f14:b0d:fa01:1822::7, 2600:1f14:b0d:fa00:8bdd::2\"; requestURI: /select/tempo/api/mcp; unsupported path requested: \"/select/tempo/api/mcp\""
}

Describe the solution you'd like

It would be great if vtselect supported the /select/tempo/api/mcp endpoint to advertise its API capabilities.

Describe alternatives you've considered

I'm investigating whether routing /select/tempo/api/mcp to mcp-victoriatraces at the VMAuth/VMUser level would help in the meantime.

Additional information

I'm running Victoria Traces v0.11.0