Notice: This is a demo server. Text to speech is expensive. You will be able to add new articles until I have spent $300. This server will be up for about a week.
If this is offline first, then why use a server at all? Why not use the native OS text-to-speech? MacOS has built in text-to-speech and so does Windows (Narrarator?)
You might be prompted to add an email account before you can change the setting in Mail. If you don't want to do that, check the preferences of the other email app. You might be able to set a default email app from there.
It says this, but Microsoft Outlook for Mac does not offer that setting. Apple Mail hides the 'Preferences' until you sign in to a mailbox, in which case it immediately downloads your email
My next side project, this gave me the goal/hope to keep it under 1mb just to be in this club! The internet is too bloated these days, and I swipe away if it takes even a few seconds to load a webpage. We can all do a little better for our users