fix(deps): re-sign all ReactiveUI/Splat deps + drop net9 MAUI targets

The samples props still pinned revoked ReactiveUI.WPF/WinForms 23.2.27 and
ReactiveUI.SourceGenerators 2.6.30 -> bump to 23.2.28 / 3.0.0. Add explicit
Splat/Splat.Builder 19.4.1 pins (resolves the CPM transitive-pinning
conflict and forces the re-signed Splat.Builder). Drop net9 MAUI
android/apple targets (workloads are EOL) — fixes the NU1202 between the
net9.0-android21.0 project TFM and the packages' net9.0-android35.0.

fix: add regression tests for #515 and #665 (#879)

fix: add regression tests for #515 and #665 (#879)

chore(deps): update dependency verify.nunit to 31.8.0 (#849)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

chore(deps): update dependency polyfill to 8.9.0 (#821)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Add .NET 9 support and update dependencies (#814)

Added .NET 9.0 target frameworks to main and test projects, updated ReactiveUI and other NuGet package versions, and refreshed copyright year to 2025. Also included .NET 9 API approval test file and updated solution and stylecop configuration.

Housekeeping Update Version (#692)

* Housekeeping Update Version

* Update to latest ReactiveUI version

Fix for Memory Leak (#660)

* Fix for Memory Leak

#659

* Update MemoryLeakTests.cs

* Remove ReadOnlyCollectionPooled

Use ReadOnlyDisposableCollection

chore(deps): update dependency dotnet-sdk to v8.0.204 (#648)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

build(deps): bump DiffEngine from 11.0.0 to 11.1.0 in /src (#510)

Bumps [DiffEngine](https://github.com/VerifyTests/DiffEngine) from 11.0.0 to 11.1.0.
- [Release notes](https://github.com/VerifyTests/DiffEngine/releases)
- [Commits](https://github.com/VerifyTests/DiffEngine/commits)

---
updated-dependencies:
- dependency-name: DiffEngine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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