[codex] reuse release artifacts for npm staging (#27312)

The release job already downloads every workflow artifact into `dist`,
but npm staging creates a new cache and downloads the six target
artifacts again.

Reuse `dist` as the staging script's artifact cache while preserving the
existing download fallback for missing artifacts and standalone callers.
The script retains ownership of temporary caches but does not delete a
caller-provided directory.

In https://github.com/openai/codex/actions/runs/27242495616, the
duplicate
download transferred 3.3 GiB and took 4 minutes 13 seconds. This should
reduce total release time by about 4 minutes.

.github/workflows/rust-release.yml

@@ -1204,6 +1204,7 @@ jobs:
           ./scripts/stage_npm_packages.py \
             --release-version "$RELEASE_VERSION" \
             --workflow-url "$workflow_url" \
+            --artifacts-dir "${GITHUB_WORKSPACE}/dist" \
             --package codex \
             --package codex-responses-api-proxy \
             --package codex-sdk

scripts/stage_npm_packages.py

@@ -101,6 +101,11 @@ def parse_args() -> argparse.Namespace:
         "--workflow-url",
         help="Optional workflow URL to reuse for native artifacts.",
     )
+    parser.add_argument(
+        "--artifacts-dir",
+        type=Path,
+        help="Directory containing previously downloaded workflow artifacts.",
+    )
     parser.add_argument(
         "--output-dir",
         type=Path,
@@ -496,6 +501,7 @@ def main() -> int:
     vendor_temp_roots: list[Path] = []
     vendor_src_by_components: dict[tuple[str, ...], Path] = {}
     artifacts_temp_root: Path | None = None
+    remove_artifacts_temp_root = False
     resolved_head_sha: str | None = None
 
     final_messages = []
@@ -506,10 +512,15 @@ def main() -> int:
                 args.release_version, args.workflow_url
             )
             print(f"Using native artifacts from {workflow_url}", flush=True)
-            artifacts_temp_root = Path(
-                tempfile.mkdtemp(prefix="npm-native-artifacts-", dir=runner_temp)
-            )
-            print(f"Caching downloaded artifacts in {artifacts_temp_root}", flush=True)
+            if args.artifacts_dir is not None:
+                artifacts_temp_root = args.artifacts_dir.resolve()
+                artifacts_temp_root.mkdir(parents=True, exist_ok=True)
+            else:
+                artifacts_temp_root = Path(
+                    tempfile.mkdtemp(prefix="npm-native-artifacts-", dir=runner_temp)
+                )
+                remove_artifacts_temp_root = True
+            print(f"Using artifact cache at {artifacts_temp_root}", flush=True)
             for components in native_component_sets:
                 vendor_temp_root = Path(
                     tempfile.mkdtemp(prefix="npm-native-", dir=runner_temp)
@@ -570,7 +581,7 @@ def main() -> int:
         if not args.keep_staging_dirs:
             for vendor_temp_root in vendor_temp_roots:
                 shutil.rmtree(vendor_temp_root, ignore_errors=True)
-        if artifacts_temp_root is not None:
+        if remove_artifacts_temp_root and artifacts_temp_root is not None:
             shutil.rmtree(artifacts_temp_root, ignore_errors=True)
 
     for msg in final_messages: