1) I would expect "signald" to be the server that clients connect to (as in, the thing provided by signal) and "signalcd" to be a client that is in the form of a daemon (akin to dhcpd vs. dhcpcd).
2) You can't use either of these names as Signal owns a trademark on their name (and even cares, as they should, particularly for a security product) and this looks like an official product in a way you can't disclaim away: come up with your own name for your daemon and then "support" signal or be "for" signal.
https://signal.org/legal/
> Signal’s Rights. We own all copyrights, trademarks, domains, logos, trade dress, trade secrets, patents, and other intellectual property rights associated with our Services. You may not use our copyrights, trademarks, domains, logos, trade dress, patents, and other intellectual property rights unless you have our written permission. To report copyright, trademark, or other intellectual property infringement, please contact [email protected].
2) You can't use either of these names as Signal owns a trademark on their name (and even cares, as they should, particularly for a security product) and this looks like an official product in a way you can't disclaim away: come up with your own name for your daemon and then "support" signal or be "for" signal.
https://signal.org/legal/
> Signal’s Rights. We own all copyrights, trademarks, domains, logos, trade dress, trade secrets, patents, and other intellectual property rights associated with our Services. You may not use our copyrights, trademarks, domains, logos, trade dress, patents, and other intellectual property rights unless you have our written permission. To report copyright, trademark, or other intellectual property infringement, please contact [email protected].