How can I programmatically gain XP which both triggers mending and is silent?

I’m working on a special world for my family and friends to play on, but with the twist that all of us have some special ability that makes us superior to the others in a certain field. "Classes" if you will.

One player wants an ability that makes them a superior user and creator of enchanted objects. What we decided on together is that they’d have a slow, passive XP generation.

We want this to activate Mending, however, so merely using the /xp command doesn’t seem to work.

I tried to summon XP orbs at their feet, but that causes a ‘ding’ every time a new point is gained–which gets quite annoying quite quickly. Adding the ‘Silent’ tag to the orb doesn’t help.

Is there a way to create an XP gain that is both silent, and activates Mending?