[Bug] Spawned agents cannot inherit parent session credentials, causing unrecoverable auth token expiration

Bug Description
Subject: Spawned agent teams cannot recover from expired auth tokens

When running a team of agents (via Task tool), if OAuth tokens expire or are invalid, each spawned agent independently prompts for /login. This creates
an unrecoverable situation because:

1. Spawned agents run as background processes — there's no way to navigate to each agent's prompt to authenticate them
2. All 5 agents blocked waiting for interactive /login input that the user can't provide
3. The parent session was already authenticated, but child agents didn't inherit valid credentials
4. Only the agent I happened to be directly interacting with could be unblocked — the rest timed out

Expected behavior: Child agents spawned from an authenticated parent session should either (a) inherit the parent's valid credentials without
re-prompting, or (b) automatically retry auth using the credential store after the user authenticates any one process.

Environment: macOS, Claude Code CLI in tmux, team of 5 agents spawned via Task tool.

Impact: Multi-agent workflows are unusable when auth tokens expire mid-session. The user has no path to unblock stuck agents, and the team degrades to
a single agent doing all the work.

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 2.1.45
• Feedback ID: 1e27cf2f-737d-4f9e-908a-5c144a50bfba

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/darronj/.local/share/claude/versions/2.1.45 (expected in multi-process scenarios)\n    at azR (/$bunfs/root/claude:3442:2098)\n    at BjA (/$bunfs/root/claude:3442:1209)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-18T15:05:40.513Z"},{"error":"Error: Request was aborted.\n    at makeRequest (/$bunfs/root/claude:366:3940)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-18T15:07:07.124Z"}]