Status line model display updates globally across all sessions when changed in one session

Description

When running multiple Claude Code sessions (e.g., main branch + worktrees), changing the model in one session updates the model/token display in the status line of ALL other sessions. The actual model used for API calls appears to remain per-session, but the status line display is shared globally, which is confusing.

Environment

• Terminal: iTerm2
• OS: macOS

Steps to reproduce

1. Open two Claude Code sessions in iTerm2 (e.g., in different worktrees or tabs)
2. In Session A, change the model (e.g., switch to Sonnet)
3. Observe Session B's status line — it now shows the new model too

Expected behavior

Status line should reflect each session's own model independently.

Actual behavior

Status line updates globally across all sessions, even though the actual model used for API calls remains per-session.