[BUG] Pro Plan OAuth broken on 2.1.1+ (2.1.0 works)

Question

## Environment
  - macOS Apple Silicon (iMac)
  - Claude Code 2.1.114: BROKEN
  - Claude Code 2.1.0: WORKS
  - Auth: Pro Plan browser OAuth

## Bug
  1. `claude` → `/login` → "Login successful"
  2. Type anything → "Not logged in"

## Workaround
  npm install -g @anthropic-ai/claude-code@2.1.0

## Expected
  OAuth should work on all versions.