feat: Add pm2 command support (list, logs, restart)

pm2 is widely used for process management in Node.js projects. Its output is heavy on ANSI formatting and table borders, making it a good candidate for RTK filtering.

Commands and output characteristics:

• pm2 list — wide ANSI table with box-drawing characters, status colors. ~30-50 lines per run.
• pm2 logs <name> --lines N — log output with ANSI timestamps. Already bounded by --lines but ANSI stripping alone would save tokens.
• pm2 restart <name> — short output (1-3 lines), lower priority.

None of these are intercepted by the hook engine:

$ rtk hook check "pm2 list"        # → exit 1, no rewrite ✗
$ rtk hook check "pm2 logs app"    # → exit 1, no rewrite ✗
$ rtk hook check "pm2 restart app" # → exit 1, no rewrite ✗

Suggested behavior:

• pm2 list → strip ANSI, compact table format, show name/status/cpu/mem columns only
• pm2 logs → strip ANSI color codes, preserve timestamps and content
• pm2 restart → passthrough (already compact)

Usage context: ~639 calls/month across Claude Code sessions (316 logs, 211 restart, 112 list).