feat: add type stubs for cli, codegen, and security modules

openapi_first/codegen_routes.pyi

@@ -0,0 +1,9 @@
+from pathlib import Path
+
+def generate_routes(
+    spec_path: Path,
+    output_dir: Path,
+    *,
+    use_models: bool = ...,
+    models_module: str = ...,
+) -> list[Path]: ...