Add Gradio process Docker health check

README.md

@@ -164,6 +164,8 @@ The Dockerfile exposes the same opt-in as
 `--build-arg SIMAM3D_INSTALL_DA3=1` for reproducible GPU research builds.
 The optional DA3 source is pinned to a specific upstream commit rather than
 tracking a moving branch.
+The container also includes a health check for the Gradio HTTP process, so a
+reachable UI can be separated from later model-inference failures.
 When DA3 is selected, its depth, confidence, extrinsics, and intrinsics shapes
 are validated at the adapter boundary; malformed results trigger the labeled V2
 fallback before any geometry export begins, and the exact fallback exception is