Tags: Swevo/HttpClient.TestKit

Add net10.0 target framework support

- Multi-target for net10.0 alongside existing TFMs
- Bump test project to net10.0 and verify test suite passes
- Update CI workflow to install .NET 10 SDK

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

chore: bump to v1.0.1 (icon refresh)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

feat: Swevo.HttpClient.TestKit v1.0.0

- FakeHttpMessageHandler with SetupGet/Post/Put/Patch/Delete
- ReturnsJson, ReturnsString, ReturnsStatusCode, Returns, Throws
- RecordedRequests for request inspection
- VerifyWasCalled/VerifyNeverCalled/VerifyCalledTimes + convenience overloads
- Configurable UnmatchedRequestHandler (default 404)
- 27/27 tests passing, zero external dependencies

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>