JJJ adds bidirectional cell navigation for jcli py:percent and .ipynb pairs.
On each # %% marker in a paired Python file, JJJ provides CodeLens actions to open or run the corresponding notebook cell, run cells above it, and review differences between the Python and notebook cell sources.
Notebook cells show status bar items that open the corresponding Python source range, report its cell number and line range, and indicate changes from the jcli pair baseline.
JJJ uses j-cli --json notebook map as its mapping source. Set jjj.jcli.executable when j-cli is not available on the extension host's PATH.
