Welcome banner duplicates (doubles) on every terminal resize

Summary

When claude is running in Terminal.app, resizing the terminal window causes the welcome banner (the pig logo + Claude Code v2.1.104 header block) to be re-rendered inline in the scrollback. Each resize roughly doubles the number of banners present — 1 → 2 → 4 → 8… — so after a few resizes the scrollback is filled with stacked banner copies.

The input prompt area still works normally; it's purely a redraw/scrollback bug, but it makes the session very messy very fast.

Environment

• Claude Code version: v2.1.104
• Model: Opus 4.6 (1M context) with high effort · Claude Max
• OS: macOS 15.7.5 (arm64, Apple Silicon)
• Terminal: Terminal.app (macOS built-in)
• Shell: zsh

Repro steps

1. Open Terminal.app
2. cd into any project and run claude
3. Wait for the welcome banner to render
4. Drag the terminal window edge to resize it (any direction)
5. Observe: a new copy of the welcome banner is drawn in the scrollback
6. Resize again → the banner count doubles
7. Repeat a few times → scrollback is full of stacked banners

Expected

Resizing the terminal should reflow the existing UI in place. The welcome banner should appear exactly once per session and should not be re-emitted into the scrollback on SIGWINCH / redraw.

Actual

Each resize appends one or more additional banners to the scrollback. The count grows (appears to double) with each resize.

Notes

• Happens in a fresh claude session with no prior activity
• Screenshots showing the stacked banners can be attached to this issue (I'll add them in a follow-up comment)