sdk: launch packaged Codex runtimes

## Why

The Python and TypeScript SDKs launch the native Codex runtime directly, so they need to consume the same package artifact shape that release jobs now produce. The runtime wheel should be built from the canonical Codex package archive rather than reconstructing a parallel layout from loose binaries.

## What Changed

- Stage `openai-codex-cli-bin` by extracting `codex-package-<target>.tar.gz` into `src/codex_cli_bin` and validating the expected package layout.
- Update release workflows to pass the generated package archive into `stage-runtime` instead of the temporary package directory.
- Update Python runtime setup to download `codex-package-*.tar.gz` release assets directly.
- Expose Python runtime helpers for the bundled package directory and `codex-path`, and prepend that path when `openai_codex` launches the installed runtime without duplicating Windows `Path`/`PATH` keys.
- Teach the TypeScript SDK to resolve package-layout optional dependencies while keeping the existing npm fallback layout, and preserve the existing Windows path variable casing when prepending `codex-path`.

## Test Plan

- `python3 -m py_compile sdk/python/scripts/update_sdk_artifacts.py sdk/python/_runtime_setup.py sdk/python/src/openai_codex/client.py sdk/python-runtime/src/codex_cli_bin/__init__.py`
- `uv run --frozen --project sdk/python --extra dev ruff check sdk/python/scripts/update_sdk_artifacts.py sdk/python/_runtime_setup.py sdk/python/src/openai_codex/client.py sdk/python/tests/test_artifact_workflow_and_binaries.py sdk/python-runtime/src/codex_cli_bin/__init__.py`
- `uv run --frozen --project sdk/python --extra dev pytest sdk/python/tests/test_artifact_workflow_and_binaries.py`
- `pnpm eslint src/exec.ts tests/exec.test.ts`
- `pnpm test --runInBand tests/exec.test.ts`

.github/workflows/rust-release-windows.yml

@@ -258,16 +258,12 @@ jobs:
 
           stage_dir="${RUNNER_TEMP}/openai-codex-cli-bin-${{ matrix.target }}"
           wheel_dir="${GITHUB_WORKSPACE}/python-runtime-dist/${{ matrix.target }}"
-          # Keep the helpers next to codex.exe in the runtime wheel so Windows
-          # sandbox/elevation lookup matches the standalone release zip.
           python "${GITHUB_WORKSPACE}/sdk/python/scripts/update_sdk_artifacts.py" \
             stage-runtime \
             "$stage_dir" \
-            "${GITHUB_WORKSPACE}/codex-rs/target/${{ matrix.target }}/release/codex.exe" \
+            "dist/${{ matrix.target }}/codex-package-${{ matrix.target }}.tar.gz" \
             --codex-version "${GITHUB_REF_NAME}" \
-            --platform-tag "$platform_tag" \
-            --resource-binary "${GITHUB_WORKSPACE}/codex-rs/target/${{ matrix.target }}/release/codex-command-runner.exe" \
-            --resource-binary "${GITHUB_WORKSPACE}/codex-rs/target/${{ matrix.target }}/release/codex-windows-sandbox-setup.exe"
+            --platform-tag "$platform_tag"
           "${RUNNER_TEMP}/python-runtime-build-venv/Scripts/python.exe" -m build --wheel --outdir "$wheel_dir" "$stage_dir"
 
       - name: Upload Python runtime wheel

.github/workflows/rust-release.yml

@@ -569,18 +569,10 @@ jobs:
             "${GITHUB_WORKSPACE}/sdk/python/scripts/update_sdk_artifacts.py"
             stage-runtime
             "$stage_dir"
-            "${GITHUB_WORKSPACE}/codex-rs/target/${{ matrix.target }}/release/codex"
+            "dist/${{ matrix.target }}/codex-package-${{ matrix.target }}.tar.gz"
             --codex-version "${GITHUB_REF_NAME}"
             --platform-tag "$platform_tag"
           )
-          if [[ "${{ matrix.target }}" == *linux* ]]; then
-            # Keep bwrap in the runtime wheel so Linux sandbox fallback behavior
-            # matches the standalone release bundle on hosts without system bwrap.
-            stage_runtime_args+=(
-              --resource-binary
-              "${GITHUB_WORKSPACE}/codex-rs/target/${{ matrix.target }}/release/bwrap"
-            )
-          fi
           python3 "${stage_runtime_args[@]}"
           "${RUNNER_TEMP}/python-runtime-build-venv/bin/python" -m build --wheel --outdir "$wheel_dir" "$stage_dir"
 
@@ -800,6 +792,20 @@ jobs:
             cp "$dmg_source" "$dest/$dmg_name"
           fi
 
+      - name: Build Codex package archive
+        shell: bash
+        env:
+          TARGET: ${{ matrix.target }}
+          BUNDLE: ${{ matrix.bundle }}
+        run: |
+          set -euo pipefail
+          bash "${GITHUB_WORKSPACE}/.github/scripts/build-codex-package-archive.sh" \
+            --target "$TARGET" \
+            --bundle "$BUNDLE" \
+            --entrypoint-dir "dist/${TARGET}" \
+            --archive-dir "dist/${TARGET}" \
+            --target-suffixed-entrypoint
+
       - name: Build Python runtime wheel
         if: ${{ matrix.bundle == 'primary' }}
         shell: bash
@@ -828,25 +834,11 @@ jobs:
             "${GITHUB_WORKSPACE}/sdk/python/scripts/update_sdk_artifacts.py" \
             stage-runtime \
             "$stage_dir" \
-            "${GITHUB_WORKSPACE}/codex-rs/dist/${{ matrix.target }}/codex-${{ matrix.target }}" \
+            "dist/${{ matrix.target }}/codex-package-${{ matrix.target }}.tar.gz" \
             --codex-version "${GITHUB_REF_NAME}" \
             --platform-tag "$platform_tag"
           "${RUNNER_TEMP}/python-runtime-build-venv/bin/python" -m build --wheel --outdir "$wheel_dir" "$stage_dir"
 
-      - name: Build Codex package archive
-        shell: bash
-        env:
-          TARGET: ${{ matrix.target }}
-          BUNDLE: ${{ matrix.bundle }}
-        run: |
-          set -euo pipefail
-          bash "${GITHUB_WORKSPACE}/.github/scripts/build-codex-package-archive.sh" \
-            --target "$TARGET" \
-            --bundle "$BUNDLE" \
-            --entrypoint-dir "dist/${TARGET}" \
-            --archive-dir "dist/${TARGET}" \
-            --target-suffixed-entrypoint
-
       - name: Upload Python runtime wheel
         if: ${{ matrix.bundle == 'primary' }}
         uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0