refactor(bootstrap): add seed loader + extractor scaffolding

SVSim.UnitTests/Importers/SeedLoaderTests.cs

@@ -0,0 +1,39 @@
+using SVSim.Bootstrap.Importers;
+
+namespace SVSim.UnitTests.Importers;
+
+public class SeedLoaderTests
+{
+    private sealed record Row(int Id, string Name);
+
+    [Test]
+    public void LoadList_returns_empty_when_file_missing()
+    {
+        string path = Path.Combine(Path.GetTempPath(), $"missing-{Guid.NewGuid()}.json");
+        var rows = SeedLoader.LoadList<Row>(path);
+        Assert.That(rows, Is.Empty);
+    }
+
+    [Test]
+    public void LoadList_deserializes_snake_case_array()
+    {
+        string path = Path.Combine(Path.GetTempPath(), $"seed-{Guid.NewGuid()}.json");
+        File.WriteAllText(path, "[{\"id\":1,\"name\":\"a\"},{\"id\":2,\"name\":\"b\"}]");
+        try
+        {
+            var rows = SeedLoader.LoadList<Row>(path);
+            Assert.That(rows, Has.Count.EqualTo(2));
+            Assert.That(rows[0].Id, Is.EqualTo(1));
+            Assert.That(rows[1].Name, Is.EqualTo("b"));
+        }
+        finally { File.Delete(path); }
+    }
+
+    [Test]
+    public void LoadObject_returns_null_when_file_missing()
+    {
+        string path = Path.Combine(Path.GetTempPath(), $"missing-{Guid.NewGuid()}.json");
+        var row = SeedLoader.LoadObject<Row>(path);
+        Assert.That(row, Is.Null);
+    }
+}