feat(csharp): MetaDataLoader.FromDirectory/FromUris/FromString static factories

Cross-language consistent factory entry points for the 99% case.
Each factory builds the appropriate Source(s) and delegates to Load().

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dmealing

server/csharp/MetaObjects.Conformance.Tests/MetaDataLoaderFactoryTests.cs

@@ -0,0 +1,36 @@
+using System.IO;
+using MetaObjects.Loader;
+using Xunit;
+
+namespace MetaObjects.Conformance.Tests;
+
+public class MetaDataLoaderFactoryTests
+{
+    [Fact]
+    public void FromDirectory_LoadsAndReturnsRoot()
+    {
+        string dir = Path.Combine(Path.GetTempPath(), "fl_" + Path.GetRandomFileName());
+        Directory.CreateDirectory(dir);
+        try
+        {
+            File.WriteAllText(Path.Combine(dir, "meta.tiny.json"),
+                "{\"metadata.root\":{\"package\":\"x\",\"children\":[]}}");
+            var result = MetaDataLoader.FromDirectory(dir);
+            Assert.Empty(result.Errors);
+            Assert.NotNull(result.Root);
+        }
+        finally
+        {
+            Directory.Delete(dir, recursive: true);
+        }
+    }
+
+    [Fact]
+    public void FromString_LoadsInlineJson()
+    {
+        var result = MetaDataLoader.FromString(
+            "{\"metadata.root\":{\"package\":\"x\",\"children\":[]}}",
+            MetaDataFormat.Json);
+        Assert.Empty(result.Errors);
+    }
+}

server/csharp/MetaObjects/Loader/MetaDataLoader.cs

@@ -74,6 +74,40 @@ public MetaDataLoader(TypeRegistry registry, bool freeze = true, bool strict = f
     private static TypeRegistry DefaultRegistry() =>
         Provider.ComposeRegistry([CoreTypes.CoreTypesProvider]);
 
+    // -------------------------------------------------------------------------
+    // Static factories (the 99% case, cross-language consistent)
+    // -------------------------------------------------------------------------
+
+    /// <summary>
+    /// Convenience: build a <see cref="DirectorySource"/> for <paramref name="directory"/>
+    /// and load all discovered files in deterministic order.
+    /// </summary>
+    public static LoadResult FromDirectory(string directory, DirectorySource.Options? opts = null)
+    {
+        var src = new DirectorySource(directory, opts);
+        var loader = new MetaDataLoader();
+        return loader.Load(src.Expand().Cast<IMetaDataSource>().ToList());
+    }
+
+    /// <summary>
+    /// Convenience: wrap each URI in a <see cref="UriSource"/> and load in order.
+    /// </summary>
+    public static LoadResult FromUris(IReadOnlyList<Uri> uris)
+    {
+        var loader = new MetaDataLoader();
+        var sources = uris.Select(u => (IMetaDataSource)new UriSource(u)).ToList();
+        return loader.Load(sources);
+    }
+
+    /// <summary>
+    /// Convenience: load a single in-memory string of the given format.
+    /// </summary>
+    public static LoadResult FromString(string content, MetaDataFormat format)
+    {
+        var loader = new MetaDataLoader();
+        return loader.Load(new IMetaDataSource[] { new InMemoryStringSource(content, format: format) });
+    }
+
     // -------------------------------------------------------------------------
     // Public properties
     // -------------------------------------------------------------------------