Add application_config table (V4 migration), repository, and REST
controller. GET /api/v1/config/{app} returns config, PUT saves and
pushes CONFIG_UPDATE to all LIVE agents via SSE. UI tracing toggle
now uses config API instead of direct SET_TRACED_PROCESSORS command.
Tracing store syncs with server config on load.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Wire getActions on ProcessorTimeline and RouteFlow to send
SET_TRACED_PROCESSORS commands to all agents of the same application.
Tracing state managed via Zustand store with optimistic UI and rollback.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>