dotslash: publish Codex entrypoints from package archives

## Summary

DotSlash should resolve the same canonical package layout used by standalone installers and npm platform packages, but it should not take the size regression of downloading gzip-compressed package archives. Installers continue to use `.tar.gz` because that format is broadly available, while DotSlash can use zstd-compressed tar archives.

This updates the package archive release helper to emit both `*.tar.gz` and `*.tar.zst` package archives from the same package directory. The Codex CLI and `codex-app-server` DotSlash release config entries now match `codex-package-<target>.tar.zst` and `codex-app-server-package-<target>.tar.zst`, with paths that select `bin/codex` or `bin/codex-app-server` inside the extracted package. The Windows release compression loop also skips prebuilt `.tar.zst` archives so it does not try to recompress them as ordinary files.

The other helper outputs stay on their existing per-binary artifacts for now.

## Test plan

- `python3 -m json.tool .github/dotslash-config.json > /dev/null`
- `bash -n .github/scripts/build-codex-package-archive.sh`
- `python3 -m py_compile scripts/codex_package/cli.py`
- `ruby -e 'require "yaml"; YAML.load_file(".github/workflows/rust-release-windows.yml"); puts "ok"'`
- Ran a Python regex smoke test that checked every updated `codex` and `codex-app-server` platform entry against the `.tar.zst` archive names emitted by `.github/scripts/build-codex-package-archive.sh`.
- Ran `scripts/build_codex_package.py` with synthetic macOS entrypoint and `rg` binaries and repeated `--archive-output` values for `.tar.gz` and `.tar.zst`, verifying both archives were written.

scripts/codex_package/cli.py

@@ -50,9 +50,11 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument(
         "--archive-output",
         type=Path,
+        action="append",
+        default=[],
         help=(
-            "Optional archive output path. Supported suffixes: .tar.gz, .tgz, "
-            ".tar.zst, .zip."
+            "Optional archive output path. May be repeated. Supported suffixes: "
+            ".tar.gz, .tgz, .tar.zst, .zip."
         ),
     )
     parser.add_argument(
@@ -130,8 +132,7 @@ def main() -> int:
     build_package_dir(package_dir, version, variant, spec, inputs)
     validate_package_dir(package_dir, variant, spec)
 
-    archive_output = args.archive_output
-    if archive_output is not None:
+    for archive_output in args.archive_output:
         archive_path = archive_output.resolve()
         write_archive(package_dir, archive_path, force=args.force)
         print(f"Built Codex package archive at {archive_path}")