Convert public static readonly fields to properties per AGENTS.md

[Copilot]

The AGENTS.md convention "Avoid public fields; prefer properties" was violated across the codebase, with 19 instances of public static readonly fields.

Changes

Converted fields to properties in:

• Program.cs: Version field → property
• All simulator classes (GhdlSimulator, ModelSimSimulator, VivadoSimulator, ActiveHdlSimulator, NvcSimulator, MockSimulator): Instance, CompileProcessor, TestProcessor fields → properties

Fixed pre-existing MSTEST0001 analyzer error:

• Added GlobalUsings.cs with [assembly: Parallelize(Scope = ExecutionScope.ClassLevel)] to satisfy MSTest 4.x requirement for explicit parallelization configuration

Example

// Before
public static readonly string Version = ...;
public static readonly GhdlSimulator Instance = new();

// After  
public static string Version { get; } = ...;
public static GhdlSimulator Instance { get; } = new();

Semantically equivalent; no functional changes.

Original prompt

Please analyze the project using the new AGENTS.md file and identify any violations of its conventions and guidelines.

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[Malcolmnixon]

Looks good