feat: first cut at actual token generation and model loading

native/metal/README.md

@@ -0,0 +1,15 @@
+# Vendored DS4 Metal boundary
+
+These files are a one-time snapshot of the DS4 Metal boundary from commit
+`efdadd41e20134af4f3381e1ed90e96fe4faef6f`:
+
+- `ds4_metal.m`
+- `ds4.h`
+- `ds4_gpu.h`
+- `ds4_ssd.h`
+- `LICENSE`
+
+The matching Metal kernels live in the repository-level `metal/` directory.
+DS4Server builds and bundles this local snapshot; it does not read a sibling
+DS4 checkout. Rust owns the model, graph, session, sampling, and lifecycle.
+Objective-C remains only at the platform Metal boundary.