hscontrol: use EmbedObject for node logging

Replace manual Uint64("node.id")/Str("node.name") field patterns with
EmbedObject(node) which automatically includes all standard node fields
(id, name, machine key, node key, online status, tags, user).

This reduces code repetition and ensures consistent logging across:
- state.go: Connect/Disconnect, persistNodeToDB, AutoApproveRoutes
- auth.go: handleLogout, handleRegisterWithAuthKey

hscontrol/policy/policy.go

@@ -136,8 +136,7 @@ func ApproveRoutesWithPolicy(pm PolicyManager, nv types.NodeView, currentApprove
 
 		if len(added) > 0 {
 			log.Debug().
-				Uint64("node.id", nv.ID().Uint64()).
-				Str("node.name", nv.Hostname()).
+				EmbedObject(nv).
 				Strs("routes.added", util.PrefixesToString(added)).
 				Strs("routes.kept", util.PrefixesToString(kept)).
 				Int("routes.total", len(newApproved)).