Fix CI, fix tests, bidirectional type bug, typos

[ptamarit]

To be reviewed commit by commit:

• ci: upgrade actions and use installed ruff instead of ruff action
  • Some actions were raising a warning about Node.js 20
  • Using the ruff action re-installs ruff (by default the latest version matching the pyproject.toml constraints); one problem is that this version will be greater than the locked one (although this can be fixed with the option version-file: "uv.lock"); the other problem is that it re-downloads ruff even though it is already installed as a dependency, so it is faster to execute it directly
• tests: initialize projects with empty token
  • Tests were blocking waiting for the token to be provided by the user on the CLI
• tests: use json.loads instead of eval
  • Entries with a null value were not properly supported by eval (raising NameError: name 'null' is not defined)
• fix: bidirectional storing matching boolean type
  • We were using strings with values "True" and "False", but this was causing SQLAlchemy to raise the error sqlalchemy.exc.StatementError: (builtins.TypeError) Not a boolean value: 'True'
• chore: fix typos
  • A few typos I found