[BUG] Dispatch pairing fails every attempt — Windows 11 Home, Build 26200

### Preflight Checklist

- [x] I have searched existing issues — found #57745 (same symptom, Windows 11 25H2, closed by stale-bot without resolution, not actually fixed)
- [x] This is a single bug report
- [x] I am using the latest version of Claude Desktop

### What's Wrong?

Dispatch has never successfully paired on this device. Every attempt from the Claude mobile app results in "ペアリングに失敗しました" (Pairing failed), with no further error detail shown on either device.

### What Should Happen?

Mobile app should pair successfully with Claude Desktop for Dispatch sessions.

### Steps to Reproduce

1. Open Claude Desktop on Windows, confirm Dispatch toggle is ON (Settings → Cowork)
2. Confirm same account signed in on both mobile and desktop
3. Open Claude mobile app → Cowork → Dispatch
4. Attempt to pair with this desktop
5. Mobile app shows "Pairing failed" every time, no connection ever established

### Claude Desktop Version

1.30096.5 (confirmed latest as of 2026-08-17)

### Operating System

Windows 11 Home, Build 10.0.26200 (same build family as #57745, which was Windows 11 Pro 25H2 Build 26200.8328)

### Troubleshooting Already Attempted

- Confirmed Dispatch toggle is ON in Settings → Cowork
- Confirmed same account signed in on mobile and desktop
- Confirmed plan is Pro (not a plan-tier issue)
- Fully quit and restarted Claude Desktop app, retried pairing
- Disconnected active Tailscale VPN on both desktop and mobile (both were connected to the same tailnet), retried pairing
- Verified outbound HTTPS connectivity to claude.ai and api.anthropic.com (both succeed)
- Verified no third-party antivirus/firewall product installed (Windows Defender only), with existing Windows Firewall rules allowing Claude inbound/outbound
- Verified Ethernet network profile is set to "Private" (not Public), which is the correct category for local discovery
- Verified Windows network discovery services (FDPHOST, FDResPub, SSDPSRV) are running
- None of the above resolved the issue — pairing fails identically every time

### Additional Information

This appears to match the exact unresolved symptom in #57745 and #45937, which were closed by inactivity, not by a fix. Filing this as a fresh report since the underlying bug appears to still be present on current builds/versions as of August 2026.

The report names no repository files, tests, or entry points; start by reproducing the pairing failure using the listed Windows, desktop, mobile, account, and network conditions. Compare the behavior with issues #57745 and #45937, then identify the relevant implementation area before deciding on a fix. Done means Dispatch pairs successfully without the reported failure.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.