Remote Control failed to connect: /login — desktop app on Windows, oauth:tokenCache empty

Problem

Running /remote-control in the Claude Code desktop app on Windows returns:

Remote Control failed to connect: /login

"Enable remote control by default" is ON in Settings → Claude Code.

Environment

• Platform: Windows 11 Home 10.0.26200
• App: Claude Code desktop app (not CLI)
• Remote Control works fine on another machine using the same account

What I found

• %APPDATA%\Claude\config.json → oauth:tokenCache exists but has no accessToken or refreshToken
• ~/.claude/.credentials.json → contains mcpOAuth entries for 18 MCP servers, but no claudeAiOauth entry
• Signing out and back into the desktop app (Settings → Account → Log out) did not repopulate either token

The chat session works fine — only the Claude Code / Remote Control feature is broken.

Expected behavior

/remote-control should connect and return a URL for controlling the session from claude.ai/code or mobile.

Question

What is the correct step to populate oauth:tokenCache / claudeAiOauth on a Windows desktop install where the account sign-in succeeded for chat but not for Claude Code features?