feat(cli): add bundled health app scaffold and init command

- ship OpenAPI-first health check template as package data
- add CLI to copy scaffold into new project directories
- include OpenAPI spec, routes, and bootstrap example
- enable fast startup for OpenAPI-first services

openapi_first/cli.py

@@ -0,0 +1,31 @@
+import shutil
+import argparse
+from pathlib import Path
+from importlib import resources
+
+
+def copy_health_app_template(target_dir: Path) -> None:
+    """
+    Copy the bundled health app template into a target directory.
+    """
+    target_dir = target_dir.resolve()
+    target_dir.mkdir(parents=True, exist_ok=True)
+
+    with resources.files("fastapi_openapi_first.templates").joinpath("health_app") as src:
+        shutil.copytree(src, target_dir, dirs_exist_ok=True)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="FastAPI OpenAPI-first scaffolding tools"
+    )
+    parser.add_argument(
+        "path",
+        nargs="?",
+        default="health-app",
+        help="Target directory for the health app",
+    )
+
+    args = parser.parse_args()
+    copy_health_app_template(Path(args.path))
+    print(f"Health app created at {args.path}")