C#: Use .NET 10 for building the extractor and running tests.

[michaelnebel]

In this PR we

• Set BMN to use .NET 10 as a fallback.
• Bump external dependencies
  • Bazel rules_dotnet til 0.21.5 with our patch on top (required for running unit tests).
  • Paket to version 10 (alpha)
• Make the extractor itself a .NET 10 project and update the build pipeline.
• Build and run unit tests using .NET 10.
• Convert .NET 9 integration tests to .NET 10.
• The dependencies were cleaned up to the extent, I think is possible. The issues below mentions similar problems when using paket for managing NuGet dependencies. In any case - this is not a blocker and we shouldn't disable the warning (for now).
  • .net 10 support fsprojects/Paket#4296
  • Warning NU1510: PackageReference ***.*** will not be pruned. Consider removing this package from your dependencies, as it is likely unnecessary. fsprojects/Paket#4307
• Manually update tests stubs to target .NET 10 (the stubs themselves need to be re-generated - this will be done in a subsequent PR).

[Copilot]

Pull request overview

This PR upgrades the C# extractor and testing infrastructure from .NET 9 to .NET 10, including updates to build tooling, integration tests, and test stubs.

• Updates .NET SDK from 9.0.300/9.0.304 to 10.0.100
• Upgrades Bazel rules_dotnet to 0.21.5 with custom patches
• Migrates target framework from net9.0 to net10.0 across all projects and tests

Reviewed changes

Copilot reviewed 297 out of 301 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
misc/bazel/registry/modules/rules_dotnet/0.21.5-codeql.1/source.json	Updates rules_dotnet source URL and integrity hash to version 0.21.5
misc/bazel/registry/modules/rules_dotnet/0.21.5-codeql.1/MODULE.bazel	Adds new MODULE.bazel configuration for rules_dotnet 0.21.5 with .NET 10.0.100 toolchain
misc/bazel/registry/modules/rules_dotnet/0.19.2-codeql.1/MODULE.bazel	Removes obsolete MODULE.bazel for rules_dotnet 0.19.2
misc/bazel/csharp.bzl	Updates TARGET_FRAMEWORK constant from net9.0 to net10.0
csharp/scripts/stubs/helpers.py	Updates stub generation scripts to use .NET 10 SDK and target framework
csharp/scripts/gen-assembly-info.py	Updates assembly info to reference .NET 10.0 instead of 9.0
csharp/scripts/create-extractor-pack.sh	Updates RuntimeFrameworkVersion to 10.0.0 for publishing
csharp/ql/test/utils/modeleditor/ApplicationModeEndpoints.expected	Updates expected test output from version 9.0.0.0 to 10.0.0.0
csharp/ql/test/resources/stubs/**/*.csproj	Updates target framework from net9.0 to net10.0 in test stub projects
csharp/ql/test/library-tests/**/*.expected	Updates expected test outputs to reflect .NET 10 assembly versions
csharp/ql/lib/change-notes/2025-12-09-bmn-default-dotnet.md	Adds change note documenting .NET 10 as default for build mode: none
csharp/ql/integration-tests/**/*.csproj	Updates target framework from net9.0 to net10.0 in integration test projects
csharp/ql/integration-tests/**/global.json	Updates SDK version from 9.0.304 to 10.0.100 in integration tests

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[michaelnebel]

@redsun82 : It looks like we need to re-apply the patch for dotnet_rules. Do you think it makes sense to get patch into rules_dotnet main?