[BUG] Read tool reports PDF is password-protected for unprotected PDFs on Windows (additional evidence for #30819)

Preflight Checklist

• [x] I have searched existing issues and found #30819 (same root cause)
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

### What's Wrong?

The Read tool reports 'PDF is password-protected' for ALL PDF files in a directory, even though none have any
security settings. Verified in Adobe Acrobat: Security Method = 'No Security' for every file. All 6 PDF files
tested fail with the same error. Files contain Japanese text.

### What Should Happen?

The Read tool should successfully read the PDF content.

### Steps to Reproduce

1. Have any PDF file without password/security settings
2. Use Read tool: Read(file_path='path/to/file.pdf', pages='1-3')
3. Error: 'PDF is password-protected. Please provide an unprotected version.'

### Claude Model

Opus 4.6 (1M context)

### Is this a regression?

No, this never worked

### Platform

Anthropic API (CLI)

### Operating System

Windows 11 Pro (10.0.26200)

### Terminal/Shell

Git Bash

### Additional Information

Related: #30819 (same bug). Adding additional evidence with 6 affected files.