feat: add streaming primitives (IChunkRenderer, IJobExecutor, NeighborSnapshots, ChunkJob)

World/Streaming/IJobExecutor.cs

@@ -0,0 +1,15 @@
+namespace VoxelEngine.World.Streaming;
+
+public interface IJobExecutor
+{
+    void Submit(Action work);
+}
+
+public sealed class ThreadPoolJobExecutor : IJobExecutor
+{
+    // Fire-and-forget: the Task is intentionally discarded. The caller's `work`
+    // delegate MUST catch its own exceptions and report them via a dedicated
+    // channel (e.g. ChunkJobResult.Error in the streaming pipeline). Unhandled
+    // exceptions here are silently lost.
+    public void Submit(Action work) => _ = Task.Run(work);
+}