[BUG] Windows: Cowork plugin marketplace empty — plugins.claude.ai does not resolve (distinct from #26951)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Cowork plugin marketplace is completely empty — no plugins appear when clicking Browse Plugins in the Customize panel.

The root cause is that plugins.claude.ai does not resolve via DNS at the OS level on Windows. This was verified by attempting to navigate to https://plugins.claude.ai in Chrome, which returned a DNS resolution failure (chrome-error://chromewebdata/). Other Anthropic domains (claude.ai, api.anthropic.com) resolve correctly.

This issue is being filed as distinct from #26951 (macOS), which describes a different failure mode: partial DNS resolution inside the Cowork VM followed by an HTTP 404. In this Windows case, DNS resolution fails entirely at the OS level — the host never receives a response for plugins.claude.ai — before any VM or HTTP layer is involved.

Note: #28853 was filed for the same Windows-specific DNS failure but was closed as a duplicate of #26951. The two issues have different root causes and likely require separate fixes.

What Should Happen?

plugins.claude.ai should resolve via DNS on Windows so that the Cowork plugin marketplace loads and displays available plugins for installation.

Error Messages/Logs

# DNS verification (via browser navigation attempt)
https://plugins.claude.ai  →  chrome-error://chromewebdata/  ❌ (DNS failure)
https://claude.ai          →  resolves correctly             ✅
https://api.anthropic.com  →  resolves correctly             ✅

Steps to Reproduce

1. Open Claude Desktop (latest version) on Windows
2. Switch to the Cowork tab
3. Click "Customize" in the left sidebar
4. Click "Browse plugins"
5. Marketplace is empty — no plugins shown

To verify DNS failure independently:

• Navigate to https://plugins.claude.ai in any browser → DNS resolution fails
• Navigate to https://claude.ai → resolves correctly

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Unknown — claude CLI not in PATH on this Windows install (accessed via Claude Desktop app)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_