Consolidate net48 into InfoBoxCore; delete legacy InfoBox.csproj

[JohannBlais]

Summary

Merges the two library projects into one. The legacy non-SDK InfoBox.csproj (net48) and the SDK-style InfoBoxCore.csproj (net8/9/10) both compiled the same shared source under InfoBox/. Now there's a single multi-targeted project.

InfoBoxCore.csproj → multi-target net48;net8.0-windows;net9.0-windows;net10.0-windows

• net48 resources: sets GenerateResourceUsePreserializedResources=true + references System.Resources.Extensions so the embedded icon resources build under the modern SDK. This is what makes dotnet build InfoBox.sln work for the whole solution — it previously failed on the legacy project with MSB3823.
• Signing uniformised: SignAssembly + key.snk added, so all four TFMs are now strong-name signed with the same key (token 6f5edd306b0cc770). Previously only net48 was signed and the modern DLLs shipped unsigned — now consistent (per the decision to uniformise).

InfoBox.csproj deleted

The InfoBox/ folder keeps the source, .resx, icon resources, key.snk, and InfoBox.nuspec; InfoBoxCore compiles them via the existing <Compile Include="..\InfoBox\**\*.cs" />.

Knock-on changes

• InfoBox.Designer (old-format net48) repointed from InfoBox.csproj → InfoBoxCore.csproj, consuming its net48 output via <SetTargetFramework>TargetFramework=net48</SetTargetFramework>. Its stale CodeAnalysisRuleSet=AllRules.ruleset references (unresolvable under dotnet, MSB3884) are removed — analysis is governed by EnableNETAnalyzers + .editorconfig.
• InfoBox.nuspec: net48 lib files now come from ..\InfoBoxCore\bin\Release\net48\. All four TFMs ship dll + pdb + 7 localization satellites.
• InfoBox.sln: InfoBox project entry removed; dead AnkhSVN SubversionScc section dropped.
• CLAUDE.md: project-structure and build sections updated.

Verified locally

Check	Result
VS MSBuild — full solution (-t:Rebuild)	✅
dotnet build InfoBox.sln (previously failed)	✅ now builds
All 4 TFMs produce signed InfoBox.dll + pdb + 7 satellites	✅
Signing token consistent across TFMs	✅ 6f5edd306b0cc770
dotnet test — InfoBoxCore.Tests / Designer.Tests	✅ 88 / 8

⚠️ Action needed before/after merge — Azure DevOps pipeline

The solution build is covered (net48 now comes from InfoBoxCore) and the nuspec paths are updated. But the pipeline's pack step lives in the Azure DevOps portal YAML, not in the repo, so I couldn't verify it. Please confirm the pack step still works — especially if it referenced InfoBox.csproj directly or ran nuget pack expecting InfoBox/bin/Release/. The nuspec now expects the net48 binaries at InfoBoxCore/bin/Release/net48/.

Also note nuget.exe is no longer restored as a side effect of the build (the old Nuget.CommandLine PackageReference was on InfoBox.csproj). If the pipeline relied on that, it needs its own nuget tool step.

🤖 Generated with Claude Code

[JohannBlais]

Azure DevOps build #292 fully green — every task succeeded: NuGet restore, Build solution, Run unit tests, Run Code Analysis, SonarCloud.

Useful finding from the task list: the CI build pipeline has no pack step (restore → build → test → code-analysis → Sonar). So NuGet packing happens in a separate release pipeline, not in CI — the CI build is therefore unaffected by the nuspec change and is confirmed working with the consolidated structure (including NuGet restore, which no longer depends on the removed Nuget.CommandLine reference).

The note about verifying the pack/release step still applies, but it's out of the CI build path.