agent endpoints: log the manifest as a structured object

Router implements zapcore.ObjectMarshaler, so registration logs the table's
size and the templates whose shape forces the matcher to search under one key
rather than assembling fields at the call site. Which templates those are is
settled when the manifest is parsed, so it is worth reporting before any
request is served; what a single match cost belongs to that request instead.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/service/agenthandler.go

@@ -228,7 +228,12 @@ func (h *AgentHandler) registerEndpoints(w *agent.Worker, sess endpoint.Session)
 	})
 	h.endpointRegistry.Register(reg)
 	w.Logger().Infow("endpoints registered",
-		"deployment", w.Deployment, "routes", len(w.Endpoints))
+		"namespace", w.Namespace,
+		"agentName", w.AgentName,
+		"deployment", w.Deployment,
+		"workerID", w.ID,
+		"manifest", manifest,
+	)
 	return reg
 }