fix ten journal defects in the list, chooser and detail view

[vyagh]

While working on a larger Journal series, there were small unrelated bugs, so here they are as their own PR first.
One fix for a commit:

• object chooser wasn't updating its list while it was open.
• The filter toolbar's background was drawn over the whole surface instead of just its own box.
• Entries made alone still showed a "Participants" heading, with nobody under it.
• The list model still carried a column for selection that nothing uses anymore.
• If an entry's title wasn't text, its row crashed instead of drawing.
• The Journal could keep showing an outdated row: a half-made one after an error, or the old title after a rename (2 commits).
• One file imported ListModel twice.
• While typing in an entry's detail view, pressing Enter or the Left arrow threw you out of the text field instead of typing in it.
• The list view found its title column by counting positions instead of using the reference it already has, which breaks the moment a column is added.

This is the base of a stacked series but merges fine on its own.

Two notes:

1. make test is already red on master before this PR, and the journal test suite arrives in the next PR, not here.
2. Tested by running the shell on a VM.