Bug fixes: Daily progress, plain text copy, and paste with whitespace

[vkbo]

Summary:

This PR fixes a few bugs:

• Daily goal progress should reset if the previous progress was recorded on an earlier date.
• Copying text from the text editor should copy as plain text, not rich text.
• Pasting rich text into the editor should not strip leading/trailing spaces.

Related Issue(s):

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All linting checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed