Status line wraps excessively on session start, normalizes after first message

Description

On session start (before the first user message is sent), the status line renders as if the terminal width is extremely narrow (~6 characters), causing it to wrap into 20+ lines vertically. After the first message is sent and a response begins, it immediately normalizes to the expected compact 2-line layout.

Steps to Reproduce

1. Open Claude Code in a terminal (tested in VS Code integrated terminal)
2. Observe the status line at the bottom before sending any message
3. Notice the status line content (timestamp, model, path, branch, context %) wraps excessively
4. Send any message
5. Status line immediately renders correctly as ~2 lines

Expected Behavior

Status line should render at the correct terminal width from session start, not just after the first interaction.

Actual Behavior

Status line appears to miscalculate terminal width on initial render, displaying all content wrapped into a very narrow column. Self-corrects after first message round-trip.

Screenshots

Before first message (broken):
Status line content like 12:03 claude-opus-4-6 /Users/.../dynamic-development-method (human-layer-full) Context 0% wraps character-by-character across 20+ lines.

After first message (correct):
Same content displays properly on 2 lines with correct terminal width.

Environment

• Claude Code CLI
• macOS (Darwin 25.1.0)
• VS Code integrated terminal
• Model: claude-opus-4-6