feat: add OAuth token keep-alive to prevent expiration - #9112

Summary

Implements an automatic keep-alive mechanism for Anthropic OAuth tokens to prevent the "Token refresh failed: 400" error that occurs after periods of inactivity.

Problem

Users report that after several hours of inactivity (especially after sleep/overnight), the Anthropic OAuth token expires and refresh fails:

Error: Token refresh failed: 400

This forces users to re-login every morning. See related issues:

• Fixes OAuth token expires after inactivity causing 'Token refresh failed: 400' #9111
• Related: Claude subscription token expires after a period of time #6559, Getting "Unauthorized: token expired" during conversation #4992

Solution

New module auth/keepalive.ts that periodically pings all logged-in Anthropic OAuth accounts using the /api/oauth/usage endpoint:

• Zero token cost - The usage endpoint doesn't consume any tokens
• Hourly ping - First ping after 5 minutes, then every 60 minutes
• Multi-account support - Pings ALL logged-in Anthropic accounts (account 1, 2, 3, etc.)
• Anthropic-only - Other providers (Copilot, OpenAI) are not affected
• Automatic - Starts with InstanceBootstrap(), no user action required
• Logged - All pings logged under auth.keepalive for debugging

Changes

• packages/opencode/src/auth/keepalive.ts - New module with keep-alive logic
• packages/opencode/src/project/bootstrap.ts - Initialize keep-alive on startup

Testing

• Run OpenCode for extended periods
• Monitor logs for auth.keepalive messages:

  auth.keepalive: pinging anthropic oauth accounts { count: 2 }
  auth.keepalive: keepalive ping successful { recordId: "...", label: "default" }
  

• Verify tokens remain valid after previously problematic timeframes