feat: dotnet bindings

[lgecse]

Description

Fixes #1124

Adds C#/.NET SDK for SLIM using uniffi-bindgen-cs to generate bindings from the existing Rust UniFFI definitions.

What's included

• C# SDK (data-plane/bindings/dotnet/): Idiomatic C# wrapper over auto-generated uniffi bindings

  • Slim - Static entry point for initialization and global service access
  • SlimService - Connection management and app creation
  • SlimApp - Session management, subscriptions, and routing
  • SlimSession - Message publishing and receiving with async support
  • SlimName - Identity parser for org/namespace/app format
  • Full async/await support with CancellationToken
  • Exception handling with SlimException

• CI/CD Integration:

  • Reusable workflow for .NET build and test (reusable-dotnet-build-and-test.yaml)
  • Integration with release-bindings.yaml for NuGet package publishing
  • Smoke tests that run without a server

• Multi-platform support: Linux (x64/arm64), macOS (x64/arm64), Windows (x64)

Usage

using Agntcy.Slim;
Slim.Initialize();
var connectionId = await Slim.ConnectAsync("http://localhost:46357");
var service = Slim.GetGlobalService();
var app = service.CreateApp("org", "namespace", "app", "my-32-char-secret-key-here!!!!!");
// ... create sessions, publish/receive messages
Slim.Shutdown();

Related: Go bindings in data-plane/bindings/go/

Type of Change

• Bugfix
• New Feature
• Breaking Change
• Refactor
• Documentation
• Other (please describe)

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced (where applicable)
• I have verified this change is not present in other open pull requests
• Functionality is documented
• All code style checks pass
• New code contribution is covered by automated tests
• All new and existing tests pass

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf CI / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Feb 6, 2026, 3:56 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud