Problem: macOS hostname command returns 'Mikes-MacBook-Air.local' but
coord messages are addressed to 'Mikes-MacBook-Air/claude-main'. Hook
script was querying for wrong session ID, so messages never displayed.
Fix: Strip .local suffix using bash parameter expansion before building
session ID.
Result: Coord messages now display correctly on macOS machines.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>