ChatService was 542 lines, mixing message delivery with the dispatch of
nine slash commands. Move the command cluster — /board, /approve, /deny,
/agent, /skill, /file, /runbook, /handoff, /escalate — into a
ChatSlashRouter that owns the approval and board-intervention services it
needs. ChatService keeps message delivery and delegates two calls.
Behaviour identical: chat-service 376 lines, router 196, full suite and
e2e green; the slash-routing governance test exercises every branch.
ZacharyZhang-NY
bd63d42aa7