Migrate to NuGet Central Package Management (CPM)

[Copilot]

Centralizes NuGet package version management using CPM to eliminate version duplication across project files.

Changes

• Directory.Packages.props (new): Central version registry at the repo root with ManagePackageVersionsCentrally=true — single source of truth for all 10 dependencies
• *.csproj files: Stripped Version attributes from all PackageReference elements; versions now resolved from Directory.Packages.props

Version unification

SonarAnalyzer.CSharp had diverged between projects (10.12.0.118525 in ProcSim, 10.19.0.132793 in ProcSim.Core). Unified to 10.19.0.132793.

<!-- Before (per-project) -->
<PackageReference Include="MaterialDesignThemes" Version="5.2.1" />

<!-- After (Directory.Packages.props) -->
<PackageVersion Include="MaterialDesignThemes" Version="5.2.1" />

<!-- After (*.csproj) -->
<PackageReference Include="MaterialDesignThemes" />

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[Copilot]

Pull request overview

This PR migrates the solution to NuGet Central Package Management (CPM), eliminating scattered per-project version declarations and creating a single source of truth for all dependency versions.

Changes:

• Adds Directory.Packages.props at the repo root with ManagePackageVersionsCentrally=true and all 10 PackageVersion entries.
• Removes Version attributes from all PackageReference elements in both .csproj files.
• Unifies the diverged SonarAnalyzer.CSharp version (was 10.12.0.118525 in ProcSim, 10.19.0.132793 in ProcSim.Core) to the newer 10.19.0.132793.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
Directory.Packages.props	New central version registry; enables CPM and defines all 10 package versions
src/ProcSim/ProcSim.csproj	Stripped Version from all 10 PackageReference elements
src/ProcSim.Core/ProcSim.Core.csproj	Stripped Version from the single PackageReference element

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

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