packaging: move rg manifest out of npm bin (#23833)

## Why

Installing `@openai/codex` currently places a Dotslash `rg` manifest at
`node_modules/@openai/codex/bin/rg`, even though the native optional
dependency already ships the actual helper under
`vendor/<target>/codex-path/rg`. The launcher prepends that `codex-path`
directory, so the top-level `bin/rg` file is redundant in the npm
install.

The remaining direct consumers of the manifest are package-building
paths: `scripts/codex_package/ripgrep.py` and
`codex-cli/scripts/install_native_deps.py`. Keeping the manifest under
`codex-cli/bin` makes it look like a shipped npm binary, so this moves
it next to the package-builder code that owns it. The checked-in
`@openai/codex` package metadata should likewise describe only the meta
package payload; generated platform packages continue to publish
`vendor`.

## What Changed

- Moved the Dotslash ripgrep manifest from `codex-cli/bin/rg` to
`scripts/codex_package/rg`.
- Updated the package builder, npm native-artifact hydrator, README, and
CLI help text to reference the new manifest location.
- Stopped `codex-cli/scripts/build_npm_package.py` from copying `rg`
into the `@openai/codex` meta package.
- Narrowed the checked-in meta package `files` whitelist to
`bin/codex.js`.

## Verification

- `python3 -m unittest discover -s scripts/codex_package -p "test_*.py"`
- `python3 -m unittest discover -s codex-cli/scripts -p "test_*.py"`
- `python3 -m py_compile codex-cli/scripts/build_npm_package.py
codex-cli/scripts/install_native_deps.py
scripts/codex_package/ripgrep.py scripts/codex_package/cli.py
scripts/stage_npm_packages.py`
- `codex-cli/scripts/build_npm_package.py --package codex --version
0.0.0-test --pack-output <tmp>/codex-meta-no-vendor.tgz`
- `tar -tf <tmp>/codex-meta-no-vendor.tgz` showed only
`package/bin/codex.js`, `package/package.json`, and `package/README.md`.
- Direct staging check showed `codex` uses `files: ["bin/codex.js"]`
while `codex-darwin-arm64` still uses `files: ["vendor"]`.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/23833).
* #23836
* __->__ #23833

codex-cli/scripts/build_npm_package.py

@@ -255,9 +255,6 @@ def stage_sources(staging_dir: Path, version: str, package: str) -> None:
         bin_dir = staging_dir / "bin"
         bin_dir.mkdir(parents=True, exist_ok=True)
         shutil.copy2(CODEX_CLI_ROOT / "bin" / "codex.js", bin_dir / "codex.js")
-        rg_manifest = CODEX_CLI_ROOT / "bin" / "rg"
-        if rg_manifest.exists():
-            shutil.copy2(rg_manifest, bin_dir / "rg")
 
         readme_src = REPO_ROOT / "README.md"
         if readme_src.exists():
@@ -316,7 +313,7 @@ def stage_sources(staging_dir: Path, version: str, package: str) -> None:
         package_json["version"] = version
 
     if package == "codex":
-        package_json["files"] = ["bin"]
+        package_json["files"] = ["bin/codex.js"]
         package_json["optionalDependencies"] = {
             CODEX_PLATFORM_PACKAGES[platform_package]["npm_name"]: (
                 f"npm:{CODEX_NPM_NAME}@"

codex-cli/scripts/install_native_deps.py

@@ -20,9 +20,10 @@ from urllib.request import urlopen
 
 SCRIPT_DIR = Path(__file__).resolve().parent
 CODEX_CLI_ROOT = SCRIPT_DIR.parent
+REPO_ROOT = CODEX_CLI_ROOT.parent
 DEFAULT_WORKFLOW_URL = "https://github.com/openai/codex/actions/runs/26131514935"  # rust-v0.132.0
 VENDOR_DIR_NAME = "vendor"
-RG_MANIFEST = CODEX_CLI_ROOT / "bin" / "rg"
+RG_MANIFEST = REPO_ROOT / "scripts" / "codex_package" / "rg"
 BINARY_TARGETS = (
     "x86_64-unknown-linux-musl",
     "aarch64-unknown-linux-musl",