C#: fields and functions in a NamespaceDeclaration are written directly into the namespace, so the output fails with CS0116 (CS0106 at file scope) #155

What's wrong

CSharpGenerator.GenerateNamespace writes every member of a namespace directly into the braced namespace: CSharpGenerator.cs#L319-L336.

Two generators then write ordinary members there:

• GenerateField: L582-L608
• GenerateFunction with enclosingType: null: L641-L660

C# has no namespace-scope fields or methods. Every other target has somewhere to put these declarations:

• C++: inline constexpr and free functions
• C, Rust and Go: module items
• Python and JavaScript: module scope

Reproduction

var ns = new NamespaceDeclaration("Geometry");
ns.Members.Add(new FieldDeclaration { Name = "Origins", Type = "int", IsConstant = true, InitialValue = new LiteralExpression<int>(2) });
var f = new FunctionDeclaration("twice") { ReturnType = "int" };
f.Parameters.Add(new Parameter("n", "int"));
f.Body.Add(new ReturnStatement(new BinaryExpression(new VariableReference("n"), BinaryOperator.Multiply, new LiteralExpression<int>(2))));
ns.Members.Add(f);

Output:

namespace Geometry
{
    public static readonly int Origins = 2;

    public int twice(int n)
    {
        return (n * 2);
    }
}

Building this gives error CS0116: A namespace cannot directly contain members such as fields, methods or statements. Putting the same members directly in a SourceFile, with no namespace, gives error CS0106: The modifier 'public' is not valid for this item instead.

The repo's own reflection-table exemplar has this shape. ExemplarReflectionTableTests.CSharp_WritesAnObjectInitialiserAndAStaticReadonlyField asserts static readonly for a FieldDeclaration inside NamespaceDeclaration("holo::components::reflection"), so the C# output that test pins does not compile (L62, L147-L153). C# has no compile test, unlike C, C++, Rust and Go, which is why this went unnoticed.

Suggested fix

• Collect a namespace's (and a file's) non-type members into a generated public static class, and mark them static. Non-type members are FieldDeclaration, FunctionDeclaration and VariableDeclaration.
• Name the class after the namespace's last segment, or use a fixed name such as Globals. Any naming convention works as long as the output compiles.
• Leave types, enums, aliases and nested namespaces where they are.

Acceptance criteria

• C# output for a namespace containing a constant table and a free function compiles.
• Add a CSharpGeneratedSourceCompilesTests, matching the C/C++/Rust/Go ones, that builds the compiled exemplar with Roslyn or dotnet build.