Adds a shared HTTP server (port 3000, configurable via WEBHOOK_PORT) that routes incoming webhooks to the correct Chat SDK adapter by path (e.g. /api/webhooks/slack, /api/webhooks/teams). Required by Slack, Teams, GitHub, Linear, and other non-gateway adapters. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>