uSync.Complete: content browser card focus, v17 to v18 forward merge

uSync.Complete: Publisher content browser cards no longer draw a focus ring over the Compare button when tabbing through card view
Cards with nothing to open drop the dead tab stop, so tab goes card, then Compare
Sync progress fixes merged to v17: push/pull progress updates now reach the browser, and the first step says what it is doing
Forward merged v17/main into v18/main: seven fixes, test dependency bumps (NUnit 5, Moq, coverlet) and the dependabot nightly feed entry
Kept v18's own npm versions where the dependabot bumps conflicted