0.25.0

Removed the legacy client SignalRConnection from CoreGame.SharedMeta.Transport.SignalR. Wire-compatible, NuGet-API-breaking for consumers that referenced the server SignalR package for their client transport.

• src/SharedMeta.Transport.SignalR/SignalRConnection.cs and MetaHubProxy.cs are deleted. The server package now contains only the server-side MetaHub (+ MetaMessagePackServerExtensions). The duplicate client SignalRConnection had drifted behind the .Client variant for several releases (no configureBuilder, no clientVersion, missing the 0.24.1 phase-2 RegisterClientSignatureAsync override — NotSupportedException on connect).
• Migration for non-Unity .NET clients (Godot, console, load tests) that used CoreGame.SharedMeta.Transport.SignalR as their client transport: switch the package reference to CoreGame.SharedMeta.Transport.SignalR.Client. Same namespace (SharedMeta.Transport.SignalR), same class name (SignalRConnection), same basic constructor (new SignalRConnection(url, accessToken)) — typically a one-line .csproj change. The .Client constructor additionally accepts configureBuilder and clientVersion (use them for MessagePack/version-gate). Unity clients are unaffected (their SignalRConnection comes from the UPM package). Server hosts are unaffected (they referenced the package only for MetaHub).