[BUG] `No visible output` retry loop in Cowork mode on Windows — persistent across sessions and app updates

## Summary

In Claude Cowork mode on Windows, every turn that ends with a tool call (including SendUserMessage) triggers the no visible output retry injection:

[Your previous response had no visible output. Please continue and produce a user-visible response.]

This creates an infinite loop. The user's messages ARE being received and SendUserMessage confirms delivery each time, but the detection logic still fires regardless.

Related Issue

Duplicate/related to #70422 (tagged platform:macOS, Claude Code), but occurring on Windows in Cowork mode and has been persistent for over one week across multiple app updates and reboots.

Steps to Reproduce

1. Open a Cowork session on Windows (Claude Desktop)
2. Have Claude perform any task involving tool calls (file ops, API calls, Confluence/Jira updates, etc.)
3. Claude ends the turn with a SendUserMessage call (confirmed: returns "Message delivered to user")
4. System injects: [Your previous response had no visible output. Please continue and produce a user-visible response.]
5. Claude responds again with a tool call → injection fires again
6. Loop continues indefinitely regardless of what tool is called last

Expected Behavior

A turn where SendUserMessage successfully returned "Message delivered to user" should be recognized as having visible output. The retry prompt should not fire.

Actual Behavior

Every turn ending with any tool call triggers the retry injection regardless of confirmed delivery. User messages still arrive and Claude's content is visible to the user, but the loop cannot be stopped.

Environment

• Platform: Windows (Claude Desktop, Cowork mode)
• Duration: Over 1 week persistent
• Tried: Multiple app updates, full reboots, new sessions — issue persists across every session

Impact

• Cowork mode unreliable for multi-step workflows
• Loop pressure caused Claude to take an action without user authorization when no user response was possible
• User cannot cleanly break the loop through normal interaction
• Plain text responses (no tool calls) break the injection temporarily but are invisible to the user per Cowork design

Workaround

None that preserves normal functionality. App restart, reboot, and updates have not resolved the issue.