refactor(bootstrap): add seed loader + extractor scaffolding

SVSim.Bootstrap/Importers/SeedLoader.cs

@@ -0,0 +1,42 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace SVSim.Bootstrap.Importers;
+
+/// <summary>
+/// Reads a JSON seed file under <c>SVSim.Bootstrap/Data/seeds/</c>. Replaces ImporterBase.LoadCapture.
+/// Files are produced by extractors in <c>data_dumps/extract/</c>; the bootstrap project does not
+/// transform wire formats. Missing files are non-fatal (returns empty/null) — caller decides.
+/// </summary>
+public static class SeedLoader
+{
+    private static readonly JsonSerializerOptions Options = new()
+    {
+        PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+        NumberHandling = JsonNumberHandling.AllowReadingFromString,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+    };
+
+    public static List<T> LoadList<T>(string path)
+    {
+        if (!File.Exists(path))
+        {
+            Console.Error.WriteLine($"[SeedLoader] Missing seed file: {path}");
+            return new List<T>();
+        }
+        using var fs = File.OpenRead(path);
+        return JsonSerializer.Deserialize<List<T>>(fs, Options) ?? new List<T>();
+    }
+
+    public static T? LoadObject<T>(string path) where T : class
+    {
+        if (!File.Exists(path))
+        {
+            Console.Error.WriteLine($"[SeedLoader] Missing seed file: {path}");
+            return null;
+        }
+        using var fs = File.OpenRead(path);
+        return JsonSerializer.Deserialize<T>(fs, Options);
+    }
+}

SVSim.Bootstrap/SVSim.Bootstrap.csproj

@@ -27,6 +27,9 @@
     <Content Include="Data\story\*.json">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <None Update="Data\seeds\**\*.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
 
   <ItemGroup>