What

Add a minimal package-windows placeholder job to the desktop nightly, beta, and release workflows.

Why

The current desktop release workflows do not consistently surface a Windows lane from main, which makes it harder to observe and evolve the Windows delivery path uniformly across channels.

How

• add a no-op Windows placeholder job to desktop-nightly.yml
• add a no-op Windows placeholder job to desktop-beta.yml
• add a no-op Windows placeholder job to desktop-release.yml
• make nightly follow-up jobs wait for the placeholder lane so the graph reflects the intended multi-platform shape

Affected areas

• Desktop app (Electron shell)
• Controller (backend / API)
• Web dashboard (React UI)
• OpenClaw runtime
• Skills
• Shared schemas / packages
• Build / CI / Tooling

Checklist

• pnpm typecheck passes
• pnpm lint passes
• pnpm test passes
• pnpm generate-types run (if API routes/schemas changed)
• No credentials or tokens in code or logs
• No any types introduced (use unknown with narrowing)

Notes for reviewers

This is intentionally a placeholder-only PR: it reserves the Windows lane in the workflow graph without publishing Windows artifacts yet.