Restore server folder and requirements.txt per user request

server/__init__.py

@@ -0,0 +1,6 @@
+"""Server package exposing ASGI app for `uvicorn server:app`."""
+
+from server.app import app, main
+
+__all__ = ["app", "main"]
+

server/app.py

@@ -0,0 +1,49 @@
+"""ASGI app entrypoint expected by openenv validate."""
+
+from __future__ import annotations
+
+import importlib.util
+import os
+import sys
+from pathlib import Path
+from typing import NoReturn
+
+import uvicorn
+
+
+def _load_impl_app() -> object:
+    """Load FastAPI app from code-review-env/server.py."""
+
+    repo_root = Path(__file__).resolve().parents[1]
+    impl_root = repo_root / "code-review-env"
+    impl_server = impl_root / "server.py"
+    if not impl_server.exists():
+        raise RuntimeError("Implementation server not found at code-review-env/server.py")
+    if str(impl_root) not in sys.path:
+        sys.path.insert(0, str(impl_root))
+    spec = importlib.util.spec_from_file_location("code_review_env_impl_server", impl_server)
+    if spec is None or spec.loader is None:
+        raise RuntimeError("Failed to create module spec for implementation server")
+    module = importlib.util.module_from_spec(spec)
+    sys.modules["code_review_env_impl_server"] = module
+    spec.loader.exec_module(module)
+    if not hasattr(module, "app"):
+        raise RuntimeError("Implementation server module does not define app")
+    return getattr(module, "app")
+
+
+app = _load_impl_app()
+
+
+def main() -> NoReturn:
+    """Run the ASGI app with uvicorn on port 7860."""
+
+    host = os.getenv("HOST", "0.0.0.0")
+    port = int(os.getenv("PORT", "7860"))
+    uvicorn.run("server:app", host=host, port=port)
+    raise SystemExit(0)
+
+
+if __name__ == "__main__":
+    main()
+