Enhancement: Show on match schedule display if a match has been posted

To help the scorekeeper keep track of what has been shown to the audience, on the match schedule list it would be helpful to have an indication that a match has been posted at least once.

Start by locating the match schedule list and the existing flow that records or exposes whether a match has been posted. Determine how the indicator should appear for posted and unposted matches, then verify the schedule display shows the state consistently.

Written by the indexing model from the issue text.