Replace direct ActivityStore injection with event-driven audit system.
Handlers emit audit events via msgBus.Broadcast(), a single subscriber
with buffered channel persists to activity_logs table.
Coverage expanded from 3 agent CRUD actions to ~65 audit points across
all HTTP handlers and WebSocket RPC methods including agents, providers,
skills, MCP servers, cron, sessions, teams, pairing, and more.
viettranx