[Bug] Windows Security block prompt ('This content is blocked by your IT admin') shown frequently during app installation

[boycez]

Description

During app installation, Windows Security displays a pop-up dialog blocking npm package / URL access:

Windows Security
This content is blocked by your IT admin
For your protection, your IT admin is not allowing you to access content from [te] npm url block.

Impact

• Severity: P0 / Bug
• Prevents smooth installation experience for users subject to corporate IT / Windows Security policies or npm URL blocking.

Triage

• Triage needed to investigate avoiding blocked npm URLs/registries during install or fallback handling.

[yikkuro]

Fixed by #106. The deployer was handing corp-blocked public npm registries (registry.npmjs.org, registry.npmmirror.com) to
pm install -g openclaw\ with a 900s timeout, so each blocked host triggered the 'blocked by your IT admin' ([Te] NPM URL Block) toast and a long hang before falling through to a reachable mirror. #106 adds a fast parallel reachability probe so blocked registries are skipped (never handed to the slow npm install), and fails fast with a clear message if none are reachable.