Restructure solution layout by module

src/Aoc/__Libraries/StellaOps.Aoc/AocGuardOptions.cs

@@ -0,0 +1,29 @@
+using System.Collections.Immutable;
+
+namespace StellaOps.Aoc;
+
+public sealed record AocGuardOptions
+{
+    private static readonly ImmutableHashSet<string> DefaultRequiredTopLevel = new[]
+    {
+        "tenant",
+        "source",
+        "upstream",
+        "content",
+        "linkset",
+    }.ToImmutableHashSet(StringComparer.OrdinalIgnoreCase);
+
+    public static AocGuardOptions Default { get; } = new();
+
+    public ImmutableHashSet<string> RequiredTopLevelFields { get; init; } = DefaultRequiredTopLevel;
+
+    /// <summary>
+    /// When true, signature metadata is required under upstream.signature.
+    /// </summary>
+    public bool RequireSignatureMetadata { get; init; } = true;
+
+    /// <summary>
+    /// When true, tenant must be a non-empty string.
+    /// </summary>
+    public bool RequireTenant { get; init; } = true;
+}