Add a note taking section

### What problem does this address?

If someone wants to take some notes while listening to a podcast they have to open another app for that and write where this note comes from.

### What is your proposed solution?

Add a screen where one can add notes for every episodes of a podcast.

### Did you search for existing feature suggestions?

- [X] I have searched for existing feature suggestions.

The issue does not name files, tests, or entry points. Start by locating the podcast and episode screens, then define how the proposed note-taking screen should associate notes with episodes and verify that notes can be added and viewed per episode.

Written by the indexing model from the issue text.