Server becomes self-contained: web/dist embedded via go:embed
(server/internal/webui), SPA served from the binary with JSON-404 guard on
/api paths, nginx web container removed from compose (31336 now maps to the
server). Clean checkouts without the UI copy build API-only.
Agent local API gains its first write endpoint, POST /v1/actions/trigger-scan
(FEAT-002 write path): group-ACL authorized, single-flight, 202/409/503
semantics. Registered agents run the same HandleScanUpdates path as a signed
scan command (empty command_id, no ack tracking); standalone agents scan
through the orchestrator into the local read model only. Also repairs
localapi tests left uncompilable by the desktop-provider parameter.