Just to echo a few comments, I'd use Emacs for this.
For time based events, you have the `run-at-time` function.
For snippets, I'd look at YASnippet[0] as they're really easy to create and you're granted a significant amount of control. Nothing you wrote sounds outside the scope of what it can provide.
On save is easy, just use `after-save-hook`. Emails is easy, too, though you will need SMTP or something.
Followup email may require custom code however Emacs 29 has SQLite support so you may be able to utilise that?
Comments
Just to echo a few comments, I'd use Emacs for this.
For time based events, you have the `run-at-time` function.
For snippets, I'd look at YASnippet[0] as they're really easy to create and you're granted a significant amount of control. Nothing you wrote sounds outside the scope of what it can provide.
On save is easy, just use `after-save-hook`. Emails is easy, too, though you will need SMTP or something.
Followup email may require custom code however Emacs 29 has SQLite support so you may be able to utilise that?
0: https://joaotavora.github.io/yasnippet/