I find it amusing how this seems to be a very common response to this sort of Ask HN question. If you want something right, you gotta do it yourself!

Here's mine: https://github.com/upvalue/meditations

It also supports habits and notes, but in mine the tasks and habits are combined. I'd like to go further like you have in combining the notes and task interfaces (right now it's basically two separate apps that happen to be in the same codebase + database).