feat: include Windows binary of the CLI in the npm release (#2040)

To date, the build scripts in `codex-cli` still supported building the
old TypeScript version of the Codex CLI to give Windows users something
they can run, but we are just going to have them use the Rust version
like everyone else, so:

- updates `codex-cli/bin/codex.js` so that we run the native binary or
throw if the target platform/arch is not supported (no more conditional
usage based on `CODEX_RUST`, `use-native` file, etc.)
- drops the `--native` flag from `codex-cli/scripts/stage_release.sh`
and updates all the code paths to behave as if `--native` were passed
(i.e., it is the only way to run it now)

Tested this by running:

```
./codex-cli/scripts/stage_rust_release.py --release-version 0.20.0-alpha.2
```

codex-cli/scripts/install_native_deps.sh

@@ -2,13 +2,8 @@
 
 # Install native runtime dependencies for codex-cli.
 #
-# By default the script copies the sandbox binaries that are required at
-# runtime. When called with the --full-native flag, it additionally
-# bundles pre-built Rust CLI binaries so that the resulting npm package can run
-# the native implementation when users set CODEX_RUST=1.
-#
 # Usage
-#   install_native_deps.sh [--full-native] [--workflow-url URL] [CODEX_CLI_ROOT]
+#   install_native_deps.sh [--workflow-url URL] [CODEX_CLI_ROOT]
 #
 # The optional RELEASE_ROOT is the path that contains package.json.  Omitting
 # it installs the binaries into the repository's own bin/ folder to support
@@ -21,18 +16,14 @@ set -euo pipefail
 # ------------------
 
 CODEX_CLI_ROOT=""
-INCLUDE_RUST=0
 
 # Until we start publishing stable GitHub releases, we have to grab the binaries
 # from the GitHub Action that created them. Update the URL below to point to the
 # appropriate workflow run:
-WORKFLOW_URL="https://github.com/openai/codex/actions/runs/15981617627"
+WORKFLOW_URL="https://github.com/openai/codex/actions/runs/16840150768" # rust-v0.20.0-alpha.2
 
 while [[ $# -gt 0 ]]; do
   case "$1" in
-    --full-native)
-      INCLUDE_RUST=1
-      ;;
     --workflow-url)
       shift || { echo "--workflow-url requires an argument"; exit 1; }
       if [ -n "$1" ]; then
@@ -81,26 +72,20 @@ trap 'rm -rf "$ARTIFACTS_DIR"' EXIT
 # NB: The GitHub CLI `gh` must be installed and authenticated.
 gh run download --dir "$ARTIFACTS_DIR" --repo openai/codex "$WORKFLOW_ID"
 
-# Decompress the artifacts for Linux sandboxing.
-zstd -d "$ARTIFACTS_DIR/x86_64-unknown-linux-musl/codex-linux-sandbox-x86_64-unknown-linux-musl.zst" \
-     -o "$BIN_DIR/codex-linux-sandbox-x64"
-
-zstd -d "$ARTIFACTS_DIR/aarch64-unknown-linux-musl/codex-linux-sandbox-aarch64-unknown-linux-musl.zst" \
-     -o "$BIN_DIR/codex-linux-sandbox-arm64"
-
-if [[ "$INCLUDE_RUST" -eq 1 ]]; then
-  # x64 Linux
-  zstd -d "$ARTIFACTS_DIR/x86_64-unknown-linux-musl/codex-x86_64-unknown-linux-musl.zst" \
-      -o "$BIN_DIR/codex-x86_64-unknown-linux-musl"
-  # ARM64 Linux
-  zstd -d "$ARTIFACTS_DIR/aarch64-unknown-linux-musl/codex-aarch64-unknown-linux-musl.zst" \
-      -o "$BIN_DIR/codex-aarch64-unknown-linux-musl"
-  # x64 macOS
-  zstd -d "$ARTIFACTS_DIR/x86_64-apple-darwin/codex-x86_64-apple-darwin.zst" \
-      -o "$BIN_DIR/codex-x86_64-apple-darwin"
-  # ARM64 macOS
-  zstd -d "$ARTIFACTS_DIR/aarch64-apple-darwin/codex-aarch64-apple-darwin.zst" \
-      -o "$BIN_DIR/codex-aarch64-apple-darwin"
-fi
+# x64 Linux
+zstd -d "$ARTIFACTS_DIR/x86_64-unknown-linux-musl/codex-x86_64-unknown-linux-musl.zst" \
+    -o "$BIN_DIR/codex-x86_64-unknown-linux-musl"
+# ARM64 Linux
+zstd -d "$ARTIFACTS_DIR/aarch64-unknown-linux-musl/codex-aarch64-unknown-linux-musl.zst" \
+    -o "$BIN_DIR/codex-aarch64-unknown-linux-musl"
+# x64 macOS
+zstd -d "$ARTIFACTS_DIR/x86_64-apple-darwin/codex-x86_64-apple-darwin.zst" \
+    -o "$BIN_DIR/codex-x86_64-apple-darwin"
+# ARM64 macOS
+zstd -d "$ARTIFACTS_DIR/aarch64-apple-darwin/codex-aarch64-apple-darwin.zst" \
+    -o "$BIN_DIR/codex-aarch64-apple-darwin"
+# x64 Windows
+zstd -d "$ARTIFACTS_DIR/x86_64-pc-windows-msvc/codex-x86_64-pc-windows-msvc.exe.zst" \
+    -o "$BIN_DIR/codex-x86_64-pc-windows-msvc.exe"
 
 echo "Installed native dependencies into $BIN_DIR"