/clear does not reset context_window.total_input_tokens in statusline JSON

Description

When using /clear to reset a Claude Code session, the context_window.total_input_tokens value passed to custom statusline scripts does not reset. The token count persists (and even slightly increases) after clearing, while it correctly resets to 0 when starting a completely new Claude Code process.

Steps to Reproduce

1. Configure a custom statusline script that displays token counts:

# ~/.claude/settings.json
{
  "statusLine": {
    "type": "command",
    "command": "~/.claude/statusline.sh"
  }
}

1. Statusline script reads from JSON input:

INPUT_TOKENS=$(echo "$JSON" | jq -r '.context_window.total_input_tokens // 0')
CONTEXT_SIZE=$(echo "$JSON" | jq -r '.context_window.context_window_size // 200000')
echo "DEBUG: ${INPUT_TOKENS}/${CONTEXT_SIZE} tokens"

1. Use Claude Code until token count is high (e.g., 430k tokens)
2. Run /clear
3. Observe token count in statusline

Expected Behavior

After /clear, total_input_tokens should reset to a low value (~10-20k for system prompt + CLAUDE.md).

Actual Behavior

• Before /clear: 430543/200000 tokens
• After /clear: 430707/200000 tokens (increased slightly, not reset)
• Starting fresh Claude process: 0/200000 tokens (correct)

Environment

• macOS (Darwin 25.2.0)
• Claude Code CLI
• VS Code integrated terminal (also reproduced in standalone terminal)

Impact

Users relying on statusline context warnings cannot use /clear to reset their session - they must quit and restart Claude Code entirely.

Workaround

Quit Claude Code process completely and start a new one (don't rely on /clear).