bug(rewrite): hook rewrites left-hand side of piped commands, breaking downstream filters

Summary

rtk rewrite (and rtk hook claude) rewrites piped commands like ps aux | grep foo | grep -v grep into rtk ps aux | grep foo | grep -v grep. Since rtk ps aux compresses/reformats output, the downstream grep no longer matches — the pipe silently returns empty results.

Reproduction

$ rtk rewrite 'ps aux | grep python | grep -v grep'
rtk ps aux | grep python | grep -v grep    # exit 0 — rewrite applied

$ ps aux | grep python | grep -v grep      # returns matching processes
$ rtk ps aux | grep python | grep -v grep  # returns nothing

Also confirmed via hook:

$ echo '{"tool_input":{"command":"ps aux | grep python | grep -v grep"}}' | rtk hook claude
{"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecisionReason":"RTK auto-rewrite","updatedInput":{"command":"rtk ps aux | grep python | grep -v grep"}}}

Expected behavior

rtk rewrite should detect pipes in the command string and either:

1. Skip rewriting entirely for piped commands, or
2. Only rewrite if downstream stages are rtk-compatible

Workaround

Wrapper script around rtk hook claude that skips piped commands:

#!/usr/bin/env bash
INPUT=$(cat)
CMD=$(echo "$INPUT" | jq -r '.tool_input.command // empty' 2>/dev/null)

case "$CMD" in
  *"|"*) exit 0 ;;
esac

echo "$INPUT" | rtk hook claude

Wire in settings.json:

"command": "~/.claude/hooks/rtk-hook-wrapper.sh"

Environment

• rtk 0.37.2 (also reproduced on 0.34.2)
• Hook: rtk hook claude (v0.37.2 built-in)
• OS: Linux x86_64