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/mapper/mapper.go

@@ -79,8 +79,7 @@ func generateUserProfiles(
 	user := node.Owner()
 	if !user.Valid() {
 		log.Error().
-			Uint64("node.id", node.ID().Uint64()).
-			Str("node.name", node.Hostname()).
+			EmbedObject(node).
 			Msg("node has no valid owner, skipping user profile generation")
 
 		return nil