Update uniffi-dart with named params

[spacebear21]

Uniffi-Dart/uniffi-dart#112 introduces named parameters in generated APIs. Update the uniffi-dart version and all dart tests accordingly. Leave in Draft until upstream PR gets merged and the ref is updated in Cargo.toml

Co-authored by Claude Opus 4.6

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[spacebear21]

I'm not sure why the C# build is failing, seems unrelated to the changes in the PR

[spacebear21]

cc @ValeraFinebits curious if have any insights on the C# error. Robot says to add this to payjoin-ffi/csharp/Payjoin.Tests.csproj:

<PropertyGroup>
  <GenerateAppHost>false</GenerateAppHost>
</PropertyGroup>

but I don't know what that means or why it just started failing now.

[benalleng]

Robot says to add this to payjoin-ffi/csharp/Payjoin.Tests.csproj:

It's my understanding that this addition just skips the apphost binary generation that NET8 is creating. I also see that there is mention of a differing dotnet version in the log /dotnet/sdk/10.0.102 I wonder if this is causing problems as we are explicitly installing 8.0.x

[chavic]

@spacebear21 @benalleng
I dug into the C# CI failure, and it looks environment-related, not from your Dart/C# changes. On February 26, 2026 (ubuntu24/20260224.36), dotnet test is running under /usr/share/dotnet/sdk/10.0.102 and fails with MSB3030 because obj/Debug/net8.0/apphost is missing; a prior green run on February 25, 2026 (ubuntu24/20260201.15) used SDK 8.0.418 and passed.

Something else can do, in .github/workflows/csharp.yml, force an isolated .NET 8 toolchain (install to a custom path), set DOTNET_ROOT and prepend it to PATH, set DOTNET_MULTILEVEL_LOOKUP=0, and add a dotnet --version check before tests to ensure the job is actually running on 8.x.

[chavic]

Looks good

[benalleng]

ACK d06394e

This was the notable comment that the second commit solves (Its just csharp semantic versioning)

Add global.json with rollForward: latestFeature so the CLI uses any 8.0.xxx but never rolls forward to 9.0+.