npm: ship platform packages in Codex package layout

## Summary

The npm platform packages should stop carrying a bespoke native layout now that the release workflow builds canonical Codex package archives. Keeping npm on the same `bin/`, `codex-resources/`, and `codex-path/` structure lets the Rust package-layout detection behave consistently across standalone, npm, and future DotSlash installs.

This changes platform npm packages to stage the `codex-package` artifact for each target under `vendor/<target>`. The Node launcher now resolves `bin/codex` and prepends `codex-path`, while retaining legacy `vendor/<target>/codex` and `vendor/<target>/path` fallback support for local development and migration. The npm staging helper downloads `codex-package` archives instead of rebuilding the CLI payload from individual `codex`, `rg`, `bwrap`, and sandbox helper artifacts.

## Test plan

- `python3 -m py_compile codex-cli/scripts/build_npm_package.py codex-cli/scripts/install_native_deps.py scripts/stage_npm_packages.py`
- `node --check codex-cli/bin/codex.js`
- `ruby -e 'require "yaml"; YAML.load_file(".github/workflows/rust-release.yml"); puts "ok"'`
- Staged a synthetic `codex-linux-x64` platform package from a canonical vendor tree and verified it copied only `bin/`, `codex-path/`, `codex-resources/`, and `codex-package.json`.
- Imported `install_native_deps.py` and extracted a synthetic `codex-package-x86_64-unknown-linux-musl.tar.gz` into `vendor/<target>`.
- `node codex-cli/bin/codex.js --version`

codex-cli/scripts/install_native_deps.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-"""Install Codex native binaries (Rust CLI, bwrap, and ripgrep helpers)."""
+"""Install Codex package archives and native helper binaries."""
 
 import argparse
 from contextlib import contextmanager
@@ -31,6 +31,7 @@ BINARY_TARGETS = (
     "x86_64-pc-windows-msvc",
     "aarch64-pc-windows-msvc",
 )
+CODEX_PACKAGE_COMPONENT = "codex-package"
 
 
 @dataclass(frozen=True)
@@ -139,11 +140,10 @@ def parse_args() -> argparse.Namespace:
         "--component",
         dest="components",
         action="append",
-        choices=tuple(list(BINARY_COMPONENTS) + ["rg"]),
+        choices=tuple([CODEX_PACKAGE_COMPONENT, *BINARY_COMPONENTS, "rg"]),
         help=(
             "Limit installation to the specified components."
-            " May be repeated. Defaults to bwrap, codex, codex-windows-sandbox-setup,"
-            " codex-command-runner, and rg."
+            " May be repeated. Defaults to codex-package and codex-responses-api-proxy."
         ),
     )
     parser.add_argument(
@@ -165,13 +165,7 @@ def main() -> int:
     vendor_dir = codex_cli_root / VENDOR_DIR_NAME
     vendor_dir.mkdir(parents=True, exist_ok=True)
 
-    components = args.components or [
-        "bwrap",
-        "codex",
-        "codex-windows-sandbox-setup",
-        "codex-command-runner",
-        "rg",
-    ]
+    components = args.components or [CODEX_PACKAGE_COMPONENT, "codex-responses-api-proxy"]
 
     workflow_url = (args.workflow_url or DEFAULT_WORKFLOW_URL).strip()
     if not workflow_url:
@@ -184,6 +178,8 @@ def main() -> int:
         with tempfile.TemporaryDirectory(prefix="codex-native-artifacts-") as artifacts_dir_str:
             artifacts_dir = Path(artifacts_dir_str)
             _download_artifacts(workflow_id, artifacts_dir)
+            if CODEX_PACKAGE_COMPONENT in components:
+                install_codex_package_archives(artifacts_dir, vendor_dir, BINARY_TARGETS)
             install_binary_components(
                 artifacts_dir,
                 vendor_dir,
@@ -199,6 +195,53 @@ def main() -> int:
     return 0
 
 
+def install_codex_package_archives(
+    artifacts_dir: Path,
+    vendor_dir: Path,
+    targets: Sequence[str],
+) -> None:
+    targets = list(targets)
+    if not targets:
+        return
+
+    print("Installing Codex package archives for targets: " + ", ".join(targets))
+    max_workers = min(len(targets), max(1, (os.cpu_count() or 1)))
+    with ThreadPoolExecutor(max_workers=max_workers) as executor:
+        futures = {
+            executor.submit(
+                _install_single_codex_package_archive,
+                artifacts_dir,
+                vendor_dir,
+                target,
+            ): target
+            for target in targets
+        }
+        for future in as_completed(futures):
+            installed_path = future.result()
+            print(f"  installed {installed_path}")
+
+
+def _install_single_codex_package_archive(
+    artifacts_dir: Path,
+    vendor_dir: Path,
+    target: str,
+) -> Path:
+    artifact_subdir = artifacts_dir / target
+    archive_path = artifact_subdir / f"codex-package-{target}.tar.gz"
+    if not archive_path.exists():
+        raise FileNotFoundError(f"Expected package archive not found: {archive_path}")
+
+    dest_dir = vendor_dir / target
+    if dest_dir.exists():
+        shutil.rmtree(dest_dir)
+    dest_dir.mkdir(parents=True, exist_ok=True)
+
+    with tarfile.open(archive_path, "r:gz") as archive:
+        archive.extractall(dest_dir, filter="data")
+
+    return dest_dir
+
+
 def fetch_rg(
     vendor_dir: Path,
     targets: Sequence[str] | None = None,