override coded virtual cards if they exist+issues

We want these cards — which return content determined by code, as virtual cards — to be overridden by an actual card by their respective names if such a card is created.

We may want to solve this by implementing all of their functionality with regular cards (*search would present an interesting challenge here).

• *recent_changes
• *search
• *broken_link

Note however that expose deck metadata in cards and expose card metadata in cards seem likely to introduce new coded virtual cards.