feat(windows): optionally expose CLI service shim

[534A4D21]

Summary

• add an opt-in -CreateCliShim option to the Windows bootstrap and installer
• generate a user-level cx-codex.cmd shim that targets the managed Release CLI
• preserve unrelated shims during uninstall and document the new option

Details

The official Windows installer currently creates cx-codex-start.cmd, but does not expose the bundled CLI as a concise cx-codex command. This change adds an opt-in shim without installing an npm global package.

When -CreateCliShim is specified, the installer creates:

%USERPROFILE%\.local\bin\cx-codex.cmd

The shim invokes the managed installation under:

%LOCALAPPDATA%\CX-Codex\dist-cli\index.js

The default installation behavior is unchanged. During uninstall, the shim is removed only when its contents target the managed CX-Codex installation; otherwise it is preserved.

Verification

• PowerShell parser checks passed for bootstrap, installer, and uninstaller scripts
• release-capabilities.json parses successfully
• modified files have no BOM
• git diff --check passed
• unit tests were not run